Wireless telecommunications system, terminal device, infrastructure equipment, integrated circuitry and methods

ABSTRACT

The present technique provides a first terminal device for exchanging signals with a wireless telecommunications network and a plurality of second terminal devices, the first terminal device configured to exchange signals with each of the plurality of second terminal devices, when the first terminal device provides a local cell for providing wireless connectivity for the plurality of second terminal devices, and to exchange signals with one or more infrastructure equipment of the wireless telecommunications network, and receive, from each of the plurality of second terminal devices served by the first terminal device when providing the local cell, suitability information indicative of the suitability of each of one or more other terminal devices or infrastructure equipment of the wireless telecommunications network to exchange signals with that second terminal device to provide for that second terminal devices another local cell.

TECHNICAL FIELD OF THE DISCLOSURE

The present disclosure relates to a wireless telecommunications system,terminal device, infrastructure equipment, integrated circuitry andmethods.

The present disclosure claims the Paris convention priority of Europeanpatent application EP16160759.3 the contents of which are incorporatedherein by reference.

BACKGROUND OF THE DISCLOSURE

The “background” description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thebackground section, as well as aspects of the description which may nototherwise qualify as prior art at the time of filing, are neitherexpressly or impliedly admitted as prior art against the presentinvention.

Mobile telecommunication systems, such as those based on the 3GPPdefined UMTS and Long Term Evolution (LTE) architecture, are able tosupport more sophisticated services than simple voice and messagingservices offered by previous generations of mobile telecommunicationsystems. For example, with the improved radio interface and enhanceddata rates provided by LTE systems, a user is able to enjoy high datarate applications such as video streaming and video conferencing onmobile communications devices that would previously only have beenavailable via a fixed line data connection.

The demand to deploy fourth generation networks is therefore strong andthe coverage area of these networks, i.e. geographic locations whereaccess to the networks is possible, is expected to increase rapidly.

However, although the coverage and capacity of fourth generationnetworks is expected to significantly exceed those of previousgenerations of communications networks, there are still limitations onnetwork capacity and the geographical areas that can be served by suchnetworks. These limitations may, for example, be particularly relevantin situations in which networks are experiencing high load and high-datarate communications between communications devices, or whencommunications between communications devices are required but thecommunications devices may not be within the coverage area of a network.

In order to address these limitations, a terminal device (or userequipment, UE) may operate to provide a local cell, the local cell beinga smaller cell at least a portion of which is provided within the largercell of a base station. This UE works simultaneously as an intermediatenode between other UEs in its vicinity and the network, as well as anintermediate node between other UEs. It communicates with its UEs inunlicensed, shared licensed or licensed bands, and backhauls to thenetwork (using licensed bands, for example). The local cell is providedat least on a temporary basis by the terminal device.

It is noted that throughout this description, when it is said (for easeof explanation) that a local cell performs an action (such astransmitting, receiving or processing signals, for example), what isactually meant is that it is the UE providing that local cell whichperforms that action. It is also noted that a local cell may also bereferred to as a virtual cell.

It is envisaged that local cells should take responsibilities like radioresource management, radio resource control (RRC) connection control,etc. instead of solely relying on an eNodeB or small cell of thenetwork. Thus, the local cell will not only relay data, but will alsohelp to organize the local network. The existence of such nodes in thenetwork will help to, for example, offload the signalling overhead ofthe eNodeB (eNB), allocate radio resource efficiently, etc.

Various advantages of establishing an RRC connection between a localcell and UE are listed below.

(1) The RRC signalling overhead between the eNB and UE is reduced. Inthe conventional network architecture, the eNB should be responsible tomaintain an RRC connection with every UE in coverage and the signallingoverhead will be non-negligible in the dense UE scenario. One solutionto reduce the signalling is to select some local cells located incoverage of the eNB. Each selected local cell will then manage the RRCconnections with UEs within its range. With use of the local cell, theeNB will not need to maintain full RRC connections with UEsindividually, but will instead only need to keep a partial RRCconnection with the UEs.(2) The use of centralized resource allocation within the local cell inorder to improve spectrum efficiency and interference mitigation.Compared with single node centralized resource allocation at the eNB,the distributed resource allocation using local cells will have themerits of flexibility and robustness. Through coordination with localcells in the network, the eNB will have better control on theinterference mitigation and resource management of the whole network,thus reducing inter-local cell interference. Furthermore, for each localcell, it is relatively easy to manage a smaller group of UEs, with afiner granularity in resources allocated to UEs within the range of thelocal cell so as to reduce the intra-local cell interference (with finergranularity, the number of resources which may be allocated isincreased, and thus the probability of users sharing the same resourcesis decreased). Thus, each local cell takes responsibility for theresource allocation to each of its UEs. The RRC connection is thenmanaged by the local cell to configure/re-configure the related physicalcontrol channels and data channels to receive the resource allocationgrant and data, respectively, as well as other configurations to supportthe resource allocation (for example, buffer status report (BSR) timers,etc.).(3) Mobility control is supported by the local cell in order toguarantee the service continuity. For an RRC_IDLE mode UE, if the UEestablishes the RRC connection with the local cell, its position will betracked by the local cell whether it is in the local cell RRC_idle state(by paging to identify Tracking Area) or in the local cell RRC connectedstate. Through the local cell (together with the position of the localcell), the eNB could track the UE even when the UE is in RRC_IDLE mode.In addition, in order to keep the service continuity, it is important tosupport fall back to the network and/or handover to another local cell.The RRC connection of the UE with the local cell supports thisrequirement.(4) Quality of Service (QoS) differentiation is supported. In futurenetworks, it is important to support QoS differentiation among users aswell as among services for each user. For a local cell, managing theresource allocations for different QoS classes is a way of improving theuser perceived quality. The local cell should also be responsible forestablishing/maintaining/releasing the corresponding radio bearers withthe UEs in order to map the logical channel configuration with theservices. The RRC connection between the local cell and UE supports theradio bearer establishment/maintenance/release.(5) Measurement report sending is supported in order to improve spectrumefficiency and support service continuity. In order to support localresource allocation by the local cell, the local cell should know thelink quality between the local cell and its scheduling UE. The UE needsto measure the channel quality with local cell and report this to thelocal cell in response to a trigger. The RRC connection between thelocal cell and UE should be established in order to configure themeasurements and send back the measurement report to the local cell.

There are a number of problems with such use of local cells, however.

Firstly, it is noted that a local cell is usually triggered in hot spotarea or in an on-demand manner. Both the local cell and UEs may move.For example, consider the following scenarios.

(1) Group split scenario. A local cell is triggered for a metro stationin rush hour. Groups of people are walking towards the metro stationwhile the other groups are leaving. For the groups moving towards thelocal cell, it's better to keep them served by the local cell. On thehand, for the leaving groups, it is better to fall back to the eNB or tohandover to another local cell.(2) Group merge scenario. A local cell V1 has been triggered for a metrostation in rush hour. The UEs approaching V1 will connect locally withit. Another group of UEs is moving towards V1. A local cell V2 has beentriggered to enhance inter-connectivity within the group. As the V2group comes closer to the range of V1, it is better to merge the V1 andV2 groups.(3) Group moving scenario. On the way home, colleagues in the sameoffice building with a similar home destination may walk together to ametro station, take the same subway line, and walk back home in the samedirection. A series of local cell may be triggered along the route andthe group of people may handover from one local cell to another.

The commonalties of these groups are summarized as below.

(1) The group members are of geographical vicinity.(2) The group members move towards approximately the same direction(3) The group members have low relative speed to each other.

There is a need to manage these groups of UEs. In particular, the groupsneed to be managed whilst taking into consideration the above-mentionedgroup characteristics. Furthermore, this should be achieved with reducedsignalling overhead and improved handover efficiency. It is noted that,in particular, a management solution is sought for local cells which aredeployed in a fixed way (that is, always there but with no or limitedmobility with respect to UEs in its vicinity) and for UEs which have afixed route or exhibit cluster behaviour. For example, for a local cellin a subway station (which may be, for example, a mobile phone of one ormore of the platform staff), the surrounding UEs exhibit clusterbehaviour as groups of people get on and off the subway, arrive at thesubway station. Also, for a local cell in a moving vehicle (such as atrain or bus), the surrounding UEs held by passengers in the vehiclehave a fixed route.

There is also a need for a local cell to efficiently use the resourcesmade available to it by the eNB for allocating to UEs connected to thelocal cell whilst, at the same time, ensuring low communication latencyfor those UEs. This applies particularly to uplink transmission from theUEs to the local cell.

SUMMARY OF THE DISCLOSURE

In a first aspect, the present technique provides a first terminaldevice for exchanging signals with a wireless telecommunications networkand a plurality of second terminal devices, the first terminal devicecomprising: a transceiver configured to exchange signals with each ofthe plurality of second terminal devices, when the first terminal deviceprovides a local cell for providing wireless connectivity for theplurality of second terminal devices, and to exchange signals with oneor more infrastructure equipment of the wireless telecommunicationsnetwork, and a controller configured to control the transceiver toreceive, from each of the plurality of second terminal devices served bythe first terminal device when providing the local cell, suitabilityinformation indicative of the suitability of each of one or more otherterminal devices or infrastructure equipment of the wirelesstelecommunications network to exchange signals with that second terminaldevice to provide for that second terminal devices another local cell;and to control the transceiver to transmit a handover command to one ormore of the plurality of second terminal devices, the handover commandinstructing the one or more second terminal devices to exchange signalswith the wireless telecommunications network via an identified moresuitable terminal device or infrastructure equipment for providing alocal cell, if one of the one or more other terminal devices orinfrastructure equipment of the wireless telecommunications networkother than the first terminal device is identified as being moresuitable for serving the one or more second terminal devices served bythe first terminal device.

In a second aspect, the present technique provides infrastructureequipment for use with a wireless telecommunications network, theinfrastructure equipment comprising: a transceiver configured toreceive, from a first terminal device of the wireless telecommunicationsnetwork, the first terminal device being configured to exchange signalswith each of a plurality of second terminal devices of the wirelesstelecommunications network, when the first terminal device provides alocal cell for providing wireless connectivity for the plurality ofsecond terminal devices, and to exchange signals with the infrastructureequipment, suitability information indicative of the suitability of oneor more other terminal devices or infrastructure equipment of thewireless telecommunications network to exchange signals with each of theplurality of second terminal devices to provide for that second terminaldevice another local cell; and a controller configured to determine, onthe basis of the suitability information, whether one of the one or moreother terminal devices or infrastructure equipment of the wirelesstelecommunications network is more suitable for serving one or more ofthe second terminal devices served by the first terminal device; in thecase that one of the one or more other terminal devices orinfrastructure equipment of the wireless telecommunications network isdetermined to be more suitable for serving one or more of the secondterminal devices served by the first terminal device, control thetransceiver to transmit information indicative of the identified one ormore other terminal devices or infrastructure equipment to the firstterminal device.

In a third aspect, the present technique provides a terminal device foruse with a wireless telecommunications network as one of a group ofterminal devices, the terminal device comprising: a transceiverconfigured to receive information indicative of a plurality ofcommunication resources, each of the indicated plurality ofcommunication resources being allocated for use by the terminal devicesof the group in transmitting signals to the wireless telecommunicationsnetwork on a contention basis; and a controller configured to controlthe transceiver to transmit a first signal to the wirelesstelecommunications network using a selected one of the allocatedcommunication resources; to determine whether the transceiver hasreceived an acknowledgement message from the wireless telecommunicationsnetwork; if it is determined that the transceiver has received anacknowledgement message, determine that the first signal has beensuccessfully received by the wireless telecommunications network; and ifit is determined that the transceiver has not received anacknowledgement message, control the transceiver to re-transmit thefirst signal to the wireless telecommunications network, wherein thecontroller is configured in combination with the transceiver to performa random selection operation by randomly selecting the one of theallocated communications resources for transmitting the first signalfrom the plurality of communication resources allocated to the group ofterminal devices.

In a fourth aspect, the present technique provides a terminal device foruse with a wireless telecommunications network, the terminal devicecomprising: a transceiver configured to transmit information indicativeof a plurality of communication resources, each of the indicatedplurality of communication resources being allocated for use by each ofthe terminal devices in a group of terminal devices in transmittingsignals to the wireless telecommunications network via the terminaldevice on a contention basis, when the terminal device provides a localcell for providing wireless connectivity for the group of terminaldevices; and a controller configured to: monitor the allocatedcommunication resources for signals received at the transceiver from theterminal devices of the group, the monitoring comprising performing anoperation with respect to each of the allocated communication resourcesto determine whether a signal has been received by the transceiver viathat communication resource from a single identified one of the terminaldevices of the group; and if it is determined that a signal has beenreceived by the transceiver via one of the allocated communicationresources from a single identified one of the terminal devices of thegroup, control the transceiver to transmit an acknowledgement message tothe identified terminal device and transmit, to each of the terminaldevices in the group, reservation information indicative of one or moreof the allocated communication resources which are reserved for use bythe identified terminal device.

In a fifth aspect, the present technique provides infrastructureequipment for use with a wireless telecommunications network, theinfrastructure equipment comprising: a transceiver configured totransmit information indicative of a plurality of communicationresources, each of the indicated plurality of communication resourcesbeing allocated for use by each of the terminal devices in a group ofterminal devices in transmitting signals to the wirelesstelecommunications network via the infrastructure equipment on acontention basis; and a controller configured to: monitor the allocatedcommunication resources for signals received at the transceiver from theterminal devices of the group, the monitoring comprising performing anoperation with respect to each of the allocated communication resourcesto determine whether a signal has been received by the transceiver viathat communication resource from a single identified one of the terminaldevices of the group; and if it is determined that a signal has beenreceived by the transceiver via one of the allocated communicationresources from a single identified one of the terminal devices of thegroup, control the transceiver to transmit an acknowledgement message tothe identified terminal device and transmit, to each of the terminaldevices in the group, reservation information indicative of one or moreof the allocated communication resources which are reserved for use bythe identified terminal device.

The foregoing paragraphs have been provided by way of generalintroduction, and are not intended to limit the scope of the followingclaims. The described embodiments, together with further advantages,will be best understood by reference to the following detaileddescription taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the present disclosure will now be described by way ofexample only with reference to the accompanying drawings wherein likeparts are provided with corresponding reference numerals and in which:

FIG. 1 provides a schematic diagram illustrating some basicfunctionality of a mobile telecommunications network/system;

FIG. 2 provides a simplified schematic diagram of the structure of adownlink of an LTE wireless access interface;

FIG. 3 provides a simplified schematic diagram of the structure of anuplink of an LTE wireless access interface;

FIG. 4 shows a schematic block diagram of a communications path betweena terminal device and infrastructure equipment via another terminaldevice providing a local cell;

FIGS. 5A-C schematically illustrate example scenarios relating to groupsof terminal devices;

FIG. 6 schematically shows an example signalling flow in which a currentserving local cell makes a handover decision;

FIG. 7 schematically shows an example signalling flow in which networkinfrastructure equipment makes a handover decision;

FIGS. 8A-B schematically show allocated communication resources whichare periodically repeated in time over one or more consecutive radioframes;

FIGS. 9A-B schematically show example processes as carried out accordingto a first embodiment of the present technique; and

FIGS. 10A-B schematically show example processes as carried outaccording to a second embodiment of the present technique.

DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 provides a schematic diagram illustrating some basicfunctionality of a mobile telecommunications network/system 100operating in accordance with LTE principles and which may be adapted toimplement embodiments of the disclosure as described further below.Various elements of FIG. 1 and their respective modes of operation arewell-known and defined in the relevant standards administered by the3GPP® body, and also described in many books on the subject, forexample, Holma H. and Toskala A [1]. It will be appreciated thatoperational aspects of the telecommunications network which are notspecifically described below may be implemented in accordance with anyknown techniques, for example according to the relevant standards.

FIG. 1 provides a schematic diagram of a conventional mobiletelecommunications system 100, where the system includes mobilecommunications devices 101, infrastructure equipment 102, and a corenetwork comprising a serving gateway node 103, a packet data gateway 104which forms a gateway to an external network 105. The infrastructureequipment 102 may also be referred to as a base station, networkelement, enhanced Node B (eNodeB or eNB) or a coordinating entity forexample, and provides a wireless access interface to the one or morecommunications devices within a coverage area or cell. The one or moremobile communications devices may communicate data via the transmissionand reception of signals representing data using the wireless accessinterface. The infrastructure equipment 102 is communicatively linkedvia the serving gateway node 103 and the packet data gateway 104 to theexternal network 105, which may be connected to one or more othercommunications systems or networks which have a similar structure tothat formed from communications devices 101 and infrastructure equipment102. The core network may also provide functionality includingauthentication, mobility management, charging and so on for thecommunications devices served by the network entity.

The mobile communications devices of FIG. 1 may also be referred to ascommunications terminals, user equipment (UE), terminal devices and soforth, and are configured to communicate with one or more othercommunications devices served by the same or a different coverage areavia the network entity. These communications may be performed bytransmitting and receiving signals representing data using the wirelessaccess interface over the two way communications links represented bylines 106 to 111, where arrows 106, 108 and 110 represent downlinkcommunications from the network entity to the communications devices andarrows 107, 109 and 111 represent the uplink communications from thecommunications devices to the infrastructure equipment 102. Thecommunications system 100 may operate in accordance with any knownprotocol, for instance in some examples the system 100 may operate inaccordance with a 3GPP Long Term Evolution (LTE) standard where theinfrastructure equipment 102 may be referred to as a base station or anenhanced Node B (eNodeB(eNB)).

Also shown in FIG. 1 is an example of a further communications device112 which exchanges data with the eNB 102 via one of the UEs 114 whichprovides a local cell to the communications device 112. Both uplink anddownlink communications between the UE 112 and eNB 102 (and thus thewireless telecommunications network) occur via the local cell 114.Uplink and downlink communication between the UE 112 and local cell 114are denoted by arrows 120 and 122, respectively. In embodiments, theremay be a plurality of UEs providing local cells, each of which allowingone or more others UEs to communicate with the network in the way shownin FIG. 1 with local cell 114 and UE 112.

LTE Wireless Access Interface

A brief description of the LTE wireless access interface is explained inthe following paragraphs with reference to FIGS. 2 and 3 to support theexplanation of the example embodiments of the present technique whichare provided in the following paragraphs.

Mobile telecommunications systems such as those arranged in accordancewith the 3GPP defined Long Term Evolution (LTE) architecture use anorthogonal frequency division modulation (OFDM) based wireless accessinterface for the radio downlink (so-called OFDMA) and a single carrierfrequency division multiple access scheme (SC-FDMA) on the radio uplink.In accordance with the present technique, the wireless access interfacefor both the down-link shown in FIG. 2 and the up-link shown in FIG. 3can provide a facility for communicating data from a UE to a mobilecommunications network via the eNB and for communicating data to the UEfrom the eNB, but can also provide communications resources forperforming D2D communications to another communications device withoutbeing communicated via the eNB. The down-link and the up-link of thewireless access interface of FIGS. 2 and 3 respectively will now beexplained.

FIG. 2 provides a simplified schematic diagram of the structure of adownlink of a wireless access interface that may be provided by or inassociation with the eNodeB of FIG. 1 when the communications system isoperating in accordance with the LTE standard. In LTE systems thewireless access interface of the downlink from an eNodeB to a UE isbased upon an orthogonal frequency division multiplexing (OFDM) accessradio interface. In an OFDM interface the resources of the availablebandwidth are divided in frequency into a plurality of orthogonalsubcarriers and data is transmitted in parallel on a plurality oforthogonal subcarriers, where bandwidths between 1.25 MHZ and 20 MHzbandwidth may be divided into 128 to 2048 orthogonal subcarriers forexample. Each subcarrier bandwidth may take any value but in LTE it isfixed at 15 KHz. As shown in FIG. 2, the resources of the wirelessaccess interface are also temporally divided into frames where a frame200 lasts 10 ms and is subdivided into 10 subframes 201 each with aduration of 1 ms. Each subframe is formed from 14 OFDM symbols and isdivided into two slots each of which comprise six or seven OFDM symbolsdepending on whether a normal or extended cyclic prefix is beingutilised between OFDM symbols for the reduction of inter symbolinterference. The resources within a slot may be divided into resourcesblocks 203 each comprising 12 subcarriers for the duration of one slotand the resources blocks further divided into resource elements 204which span one subcarrier for one OFDM symbol, where each rectangle 204represents a resource element. More details of the down-link structureof the LTE wireless access interface are provided in Annex 1.

FIG. 3 provides a simplified schematic diagram of the structure of anuplink of an LTE wireless access interface that may be provided by or inassociation with the eNodeB of FIG. 1. In LTE networks the uplinkwireless access interface is based upon a single carrier frequencydivision multiplexing FDM (SC-FDM) interface and downlink and uplinkwireless access interfaces may be provided by frequency divisionduplexing (FDD) or time division duplexing (TDD), where in TDDimplementations subframes switch between uplink and downlink subframesin accordance with predefined patterns. However, regardless of the formof duplexing used, a common uplink frame structure is utilised. Thesimplified structure of FIG. 3 illustrates such an uplink frame in anFDD implementation. A frame 300 is divided in to 10 subframes 301 of 1ms duration where each subframe 301 comprises two slots 302 of 0.5 msduration. Each slot is then formed from seven OFDM symbols 303 where acyclic prefix 304 is inserted between each symbol in a manner equivalentto that in downlink subframes. More details of the LTE up-linkrepresented in FIG. 3 are provided in Annex 1.

Structure of UE, Local Cell and eNB

FIG. 4 shows a schematic block diagram of a communications path betweenthe UE 112 and the eNB 102 via the UE 114 providing a local cell. Asshown in FIG. 4 the UE 112 includes a transmitter 401, a receiver 402(the transmitter 401 and receiver 402 together forming a transceiver)and a controller 404 to control the transmission and reception ofsignals to the UE 114 providing a local cell. The up-link signals arerepresented by an arrow 120 which corresponds to that shown in FIG. 1and the downlink signals are shown by an arrow 122, which corresponds tothat shown in FIG. 1. The local cell UE 114 could be a conventional UEand so includes also a transmitter 401, receiver 402 (the transmitter401 and receiver 402 together forming a transceiver) and a controller404. The local cell UE 114 transmits signals on the uplink as shown byan arrow 107 and receives signals on the downlink as represented by anarrow 106 to and from the eNB 102, respectively. The eNB 102 includes atransmitter 406, a receiver 408 (the transmitter 406 and receiver 408together forming a transceiver) and a controller 410 which may include ascheduler for scheduling the transmission and reception of signals onthe downlink and the uplink in accordance with the wireless accessinterface shown in FIGS. 2 and 3.

Local Cell Group Handover

A first embodiment of the present technique provides an arrangement formanaging groups of UEs which communicate with the network using a localcell (such as local cell UE).

FIGS. 5A-C schematically illustrates the three example scenariospreviously discussed. In particular, FIG. 5A shows the group splitscenario (1), FIG. 5B shows the group merge scenario (2) and FIG. 5Cshows the group moving scenario. In each of FIGS. 5A-C, there is shown afirst base station 102A in communication with a first local cell 114A, asecond base station 102B in communication with a second local cell 114Band six UEs 112A-F. Furthermore, each of the UEs 112A-F is shown with arespective motion vector 500A-F indicating a direction of movement ofthe UE.

In the group split scenario shown in FIG. 5A, each of the UEs 112A-C ismoving towards the local cell 114A and each of the UEs 112D-F is movingaway from the local cell 114A. The local cell 114A is a stationary (orapproximately stationary) local cell located at a subway station forexample, and the UEs 112A-C are being carried by passengers entering thesubway station where as the UEs 112D-F are being carried by passengersleaving the subway station. In this case, in order to maintain effectivecommunication with the network for all the UEs 112A-F, it is desirablefor the UEs 112A-C to become a distinct group of UEs communicating withthe network via local cell 114A and for the UEs 112D-F to become anotherdistinct group of UEs communicating with the network using anothernetwork node (such as local cell 114B or even eNB 102B).

In the group merge scenario shown in FIG. 5B, each of the UEs 112A-F ismoving towards the local cell 114A. For example, the UEs 112A-F may bebeing carried by passengers entering the subway station within which thelocal cell 114A is located. In this case, in order to maintain effectivecommunication with the network for all the UEs 112A-F, it is desirablefor all the UEs 112A-F to become a single group of UEs communicatingwith the network via local cell 114A. Thus, for example, if UEs 112A-Care currently communicating with the network via local cell 114A whilstUEs 112D-F are currently communicating with the network via anothernetwork node (such as local cell 114B or eNB 102B), then it is desirablefor the UEs 112D-F to stop communicating with the network via this othernetwork node and to instead communicate with the network using the localcell 114A. This results in all UEs 112A-F forming a single group andcommunicating with the network via the same local cell 114A.

In the group moving scenario shown in FIG. 5C, each of the UEs 112A-F ismoving away from the local cell 114A. For example, the UEs 112A-F may bebeing carried by passengers leaving the subway station within which thelocal cell 114A is located. In this case, in order to maintain effectivecommunication for all the UEs 112A-F as they move away from the localcell 114A, it is desirable for each of the UEs 112A-F to stopcommunicating with the network via the local cell 114A and to begincommunicating with the network via another network node (such as thelocal cell 114B or eNB 102B). This results in each of the UEs 112A-Fchanging the network node via which they communicate with the networkbut remaining as part of the same group.

It is noted that, in the context of the present embodiment, the term“group” refers to a selection of one or more UEs from a set of UEs allcommunicating with the network via the same network node. The networknode via which a particular UE communicates with the network may bereferred to as the serving network node for that UE.

Thus, it can be seen that in each of the above-mentioned scenarios, themost appropriate serving network node must be determined for each UE orUE group. Furthermore, once the most appropriate serving network nodehas been determined, and it is found that the most appropriate servingnetwork node is not the current serving local cell, handover from thecurrent serving local cell to the newly determined serving network nodemust be implemented. An arrangement for determining the most appropriateserving network node and implementing handover is provided by thepresent embodiment.

The most appropriate serving network node for a particular UE can bedetermined by the current serving local cell or serving eNB of that UEon the basis of signal measurements from various network nodes in thevicinity of the UE. Specifically, each UE may measure a characteristicof a signal from each network node in its vicinity (for example, aReference Signal Received Power (RSRP) or a Reference Signal ReceivedQuality (RSRQ) associated with each network node), and report themeasurements to the current serving local cell or serving eNB. Adecision on the most appropriate serving network node can then be madeon the basis of this measurement report.

For the measurement reporting, it is not only the best measurementresults (relating, for example, to network nodes for which the highestRSRP values are measured) which will be reported, but also the worstones (this may be useful for determining which UEs should be left withthe current serving local cell during a group split scenario, forexample) and equal or similar ones (this may be useful for a group mergescenario, for example). For example, consider a group split scenario inwhich hypothetical UEs A, B, C, D are within the group of local cell 1.UEs A and B are determined to each have a good link quality with localcell 2, but UEs C and D are determined to have the worst link qualitywith local cell 2 (out of all the local cells in range of UEs C and D).UEs A and B will thus be split from the local cell 1 group. As anotherexample, consider a group merge scenario in which one group ofhypothetical UEs A and B are communicating with local cell 1 and anothergroup of hypothetical UEs C and D are communicating with local cell 2.If the link quality of UEs C and D with local cell 1 is similar to thatwith local cell 2, then the two groups could be merged. The measurementreport will be sent to the current serving local cell from a UE. Thecurrent serving local cell may then make a decision as to whether or notto initiate a handover operation to a different serving network node, ormay combine the measurement reports of its UEs and send the combinedreport to its associated eNB for the eNB to make the decision andinitiate the handover.

Other information can also be indicated with the measurement report(either as part of the measurement report or as a separate report) tothe current serving local cell by the UEs in the group in order for themost appropriate serving network node for each UE to be determined. Inparticular, assistant information relating to, for example, the movingspeed and/or direction of each UE, and/or identified UE behaviour (forexample, on a train, in a subway, on the way to the office, etc.) may befed back to local cell and/or eNB in order for the most appropriateserving network node for each UE to assist in the determination of themost appropriate network node. It is noted that a determination of themost appropriate network node and the decision to handover to thatnetwork node may be referred to as a handover decision.

In some embodiments (relating to, for example, group split or groupmerge scenarios), the handover decision is made by a local cell. Forexample, an initial serving local cell (source local cell) may decidewhich UEs in its group are to be handed over to a new serving local cell(target local cell) and which UEs group will stay. This decision(including the new serving local cell to which the leaving UEs are to behanded over) is made on the basis of the measurement reports receivedfrom each UE in the group. Once the decision has been made, the sourcelocal cell will notify the target local cell of the group informationindicative of the group of UEs to be handed over. The target local cellwill then undertake admission control and prepare radio resourceaccordingly. If necessary, the target local cell may ask its associatedeNB to re-allocate resources for use in communicating with the handedover UEs. In some cases, the target local cell will only accept a subsetof the UEs initially identified for handover (as may occur, for example,if the target local cell does not have capacity to take all theidentified UEs). In such a scenario, both the source and target localcell may decide which subset of the group of UEs will be handed overaccording to a suitable characteristic associated with group of UEs(such as the data traffic associated with each UE, Quality of Service(QoS) requirements of each UE, etc.). After receiving the confirmationfrom the target local cell that it is able to accept the group of UEsidentified for handover (or at least a subset of the group), the sourcelocal cell then issues a handover command to each UE identified forhandover.

In other embodiments (relating to, for example, group moving, groupmerge or inter-eNB local cell handover), the handover decision is madeby an eNB. For example, the eNB will decide which UEs associated with aparticular source local cell will be handed over (and to which targetlocal cell) based on the measurement report of each UE received by thesource local cell (or even received directly from each UE). The eNB willthen notify the group information indicative of the group of UEs to behanded over to the target local cell, and re-allocate resources for thegroup if necessary. For the case of inter-eNB local cell handover (whenthe source and target local cells are connected to different eNBs), thesource eNB will notify the group information to the target eNB. If thetarget local cell accepts the group handover, then the eNB will notifythe source local cell to send the handover command or the eNB will sendthe handover command by itself.

The handover command and corresponding configuration (that is, thecommon information for all UEs in RRCConnectionReconfiguration messageincluding MobilityControlInformation) will be sent to the UEs in thegroup to be handed over in a groupcast-like manner. For example, aspecific group Radio Network Temporary Identifier (RNTI) will beallocated. For the specific UE information, a new UE identifier (UE-ID)and dedicated Random Access Channel (RACH) preamble (if necessary) willbe sent to each UE individually, for example.

Some examples are now given for identifying a group of UEs that need tobe handed over.

In one example, link quality differentiation can be used. In this case,a source local cell or eNB may configure the measurement of neighbouringlocal cells or cells by each UE. For example, from the measurementreport, it may be determined that some UEs have a good link with thecurrent serving local cell while the others have a bad link with thecurrent serving local cell. Similarly, it may be determined that someUEs have a good link with a particular potential target local cell whilethe others have a bad link with that particular potential target localcell. The link quality may be determined by each UE on the basis of ameasured link quality (for example, RSRP or RSRQ) of each neighbouringlocal cell, for example. By reviewing the measurement reports from eachUE connected to the source local cell, the most appropriate local cellfor each UE may be determined and handover may be initiated asappropriate. Handover may result in, for example, the UEs with a goodlink quality with a particular local cell forming a group connected tothat local cell while the other UEs with bad link quality form one ormore other groups connected to one or more other local cells.

In another example, UEs within a certain proximity to each other (asdetermined by a predetermined proximity threshold, for example) and witha similar direction of movement will form a group. These UEs are thenhanded over, at the same time, between appropriate local cells as thegroup moves. As the group moves, the link quality for each UE in thegroup associated with the source local cell will become continuouslyweaker over a predetermined time period where as the link qualityassociated with an appropriate target local cell will becomecontinuously stronger over that predetermined time period. The sourcelocal cell or eNB may then initiate handover to the determined targetlocal cell, when appropriate.

In another example, a target local cell is determined through one ormore behaviour identification technologies so that UEs exhibiting thesame behaviour will be grouped. For example, with a behaviouridentification technology which is able to determine whether or not aparticular UE is on a train, UEs on the train will be included in afirst group (with a first local cell) where as UEs not on the train (butinstead, on the platform, for example) will be included in a secondgroup.

Each UE will be triggered to send its measurement report to its servinglocal cell based on a predetermined trigger event (for example, theelapse of a predetermined period of time or a certain change in themeasurements related to each local cell or cell in the vicinity of theUE). In the case that it is the eNB which makes the handover decision,the local cell will a send combined measurement report. The combinedmeasurement report may indicate, for example, the signal measurementreports (or a subset of the signal measurement reports) of eachindividual UE, speed and/or direction characteristics of the UEsrelative to the current serving local cell (including, for example,average speed and/or direction of the group relative to the currentserving local cell) and/or group behaviour of the UEs (indicative of,for example, whether the group of UEs are getting on or off train). Inthis case, because the combined measurement report is sent from thecurrent serving local cell to the eNB (rather than each UE sending anindividual measurement report to the eNB), the signalling between eachindividual UE and eNB will be reduced.

The assistant information which may be included with the measurementreport (either as part of the measurement report or as a separatereport) provided to the current serving local cell by each UE is used toassist in the group handover decision. Examples of assistant informationinclude the location of each UE (as determined by Global NavigationSatellite System (GNSS) or as determined relative to the current servinglocal cell on the basis of the link quality for each UE, for example),the direction in which each UE is travelling relative to the currentlocal cell (as determined on the basis of whether the link qualitybecomes continuously stronger (indicating that the UE is moving towardsthe local cell) or continuously weaker (indicating that the UE is movingaway from the local cell) over a predetermined time period), and userbehaviour associated with each UE (such as whether the UE is entering orleaving a train, for example). In one embodiment, the assistantinformation could also be carried in a discovery message transmitted byeach UE to local cells within its vicinity (this may occur when a UE isturned on and initially attempts to connect to the network, forexample).

In addition, each local cell may transmit corresponding assistantinformation to UEs in its vicinity in order to aid in the selection ofan appropriate local cell for each UE. For example, a local cellspecifically designated for use in a subway station may broadcastinformation identifying that local cell as a subway station local cell(this may be implemented using a special local cell ID which isassociated subway station local cells, for example). When a UEdetermines that it has entered the subway station, it can thusdetermine, from the information broadcast from the subway station localcell, that this local cell is the most appropriate. This information canbe indicated in a discovery message or measurement report transmittedfrom that UE, and thus a connection between the UE and subway stationlocal cell can be initiated or the UE can be handed over from itsoriginal local cell to this subway station local cell. Other local cellcharacteristics (such as information indicative that a local cell islocated at a bus stop, has specifically been designated as a hotspot, isa fixed local cell or is a mobile local cell, for example), could alsobe transmitted to UEs and used in a similar way.

Based on the measurement report and assistant information (which eachconstitute forms of suitability information indicative of thesuitability of each potential local cell or eNB to which UEs may behanded over) provided by each UE, a group of UEs will be identified andhandover decision may be made. Depending on which element of the networkmakes the handover decision (for example, the local cell or the eNB),the signalling flow may be different.

FIG. 6 schematically shows an example signalling flow in which thecurrent serving local cell makes the handover decision. FIG. 6 shows agroup split scenario, in which, after local cell VC1 receives ameasurement report from each of its connected UEs, it decides to splitthe UEs into two groups G1 and G2. G2 will be handed over to local cellVC2 and G1 will remain connected to local cell VC1. Both VC1 and VC2 areconnected eNB 102.

At step 600, VC1 transmits measurement and assistant informationconfiguration information to the UEs in each of the groups G1 and G2.This instructs each of the UEs in the groups G1 and G2 to transmit theirrespective measurement reports and assistance information to VC1, whichthe UEs do at steps 602 and 604. At step 606, VC1 makes a group handoverdecision for the group on the basis of the measurement reports andassistance information. In this case, the decision is for the UEs ingroup G2 to be handed over to VC2. At step 608, VC1 thus transmits agroup handover request to VC2. At step 610, VC2 transmits a resourcepool request to eNB 102. The resource pool request comprises a requestfor a pool of resources for use by VC2 in communicating with each of theUEs in group G2. At step 612, VC2 receives the resource pool allocationfrom the eNB 102. It is noted that if VC2 already has appropriatecommunication resources for use in communicating with each of the UEs ingroup G2, then steps 610 and 612 may be omitted. At step 614, VC2carries out an admission control procedure and then, at step 616,transmits a group handover request acknowledgement to VC1. This informsVC1 that VC2 is able to become the serving local cell for the UEs ofgroup G2. In response, in step 618, VC1 transmits a group handovercommand to each of the UEs in group G2 and, in step 620, forwards datarelating to the UEs in group G2 (including data required by VC2 inestablishing a connection with the UEs of group G2) to VC2. In response,at step 622, a random access channel (RACH) is established between VC2and each of the UEs in group G2 so as to allow random accesscommunication to be established between VC2 and the UEs.

The communication path between each of the UEs in the group G2 and thenetwork is therefore switched from being via VC1 to being via VC2 atstep 624. Finally, at step 626, VC1 (which is now only providing theserving local cell for the UEs of group G1) may transmit a resource poolre-allocation request to the eNB 102. The resource pool re-allocationrequest indicates the resources that are no longer needed by VC1. Atstep 628, the eNB 102 then re-allocates these resources and transmits aresource pool re-allocation acknowledgement message back to VC1 once there-allocation is complete. It is noted that steps 626 and 628 areoptional. However, by including them, resources which are no longerneeded by the source local cell VC1 are freed up for use by otherelements of the network, thus providing more efficient use of networkresources.

FIG. 7 schematically shows an example signalling flow in which the eNB102 makes the handover decision. FIG. 7 again shows a group splitscenario, in which, after local cell VC1 receives a measurement reportfrom each of its connected UEs, the eNB 102 decides to split the UEsinto two groups G1 and G2. G2 will be handed over to local cell VC2 andG1 will remain connected to local cell VC1. In this case, VC1 isconnected to a first eNB (eNB1) whilst VC2 is connected to a second eNB(eNB2).

At step 700. VC1 transmits measurement and assistant informationconfiguration information to the UEs in each of the groups G1 and G2.This instructs each of the UEs in the groups G1 and G2 to transmit theirrespective measurement reports and assistance information to VC1, whichthe UEs do at steps 702 and 704. At step 706, the measurement reportsfrom each UE are combined to form a combined measurement report and thisis transmitted, along with the assistant information associated witheach UE, to eNB. The combined measurement report and UE assistantinformation together form a group report, and it is this which istransmitted at step 706. At step 708, eNB1 makes a group handoverdecision for the group on the basis of the measurement reports andassistance information. Again, in this case, the decision is for the UEsin group G2 to be handed over to VC2. At step 710, eNB1 transmits agroup handover request to eNB2 (since VC2 is connected to eNB2). eNB2then carries out an admission control procedure at step 712 and, at step714, allocates a resource pool to VC2 for use in communicating with eachof the UEs in group G2. At step 716, eNB2 transmits a group handoverrequest acknowledgement to eNB1. This informs eNB1 that VC2 is able tobecome the serving local cell for the UEs of group G2. In response, instep 718, eNB1 transmits a group handover command to VC1 which, in turn,forwards the group handover command to each of the UEs in group G2 atstep 720. In step 722, VC1 then forwards data relating to the UEs ingroup G2 (including data required by VC2 in establishing a connectionwith the UEs of group G2) to VC2. This data may be forwarded directly toVC2 (in the case that signals can be exchanged directly between VC1 andVC2 without the use of eNBs) or, alternatively, may be forwarded to VC2via eNB1 and eNB2. In response, at step 724, a random access channel(RACH) is established between VC2 and each of the UEs in group G2 so asto allow random access communication to be established between VC2 andthe UEs. The communication path between each of the UEs in the group G2and the network is therefore switched from being via VC1 to being viaVC2 at step 624. Finally, at step 728, VC1 (which is now only providingthe serving local cell for the UEs of group G1) may transmit a resourcepool re-allocation request to eNB1. The resource pool re-allocationrequest indicates the resources that are no longer needed by VC1. Atstep 730, eNB1 then re-allocates these resources and transmits aresource pool re-allocation acknowledgement message back to VC1 once there-allocation is complete. It is noted that, again, steps 728 and 730are optional. However, by including them, resources which are no longerneeded by the source local cell VC1 are freed up for use by otherelements of the network, thus providing more efficient use of networkresources.

It is noted that the handover request transmitted at step 608 and 710may comprise, for example, group information (this being collectiveinformation relating to the group, such as the group size, groupresources demand, average group moving speed, etc.), individual UEinformation (this being information relating to each individual UE inthe group, such as RRC context information including the UE identifier,link quality with the target local cell, radio bearer contextinformation including QoS requirement, resources demand, data traffictype, etc.) and identifiers of the target local cell (VC2) andcorresponding target cell (the target cell being eNB 102 in FIG. 6, whenboth VC1 and VC2 are connected to the same cell, and eNB2 in FIG. 7,when VC2 is connected to eNB2).

As previously mentioned, in order for VC2 to accept the group G2, thecurrent resource pool available to VC2 may not enough. As a result,additional resources may be allocated to it (as occurs in steps 612 and714). The additional resources may be determined based on, for example,group information (this again being collective information relating tothe group, such as the group size, group resources demand, average groupmoving speed, etc.). The resulting resource pool allocation message(transmitted at steps 612 and 714) may contain the additional resourcepool allocation, a completely new resource pool, or the rejection of therequest (in this case, it may not be possible for the group to be handedover to VC2, and thus another target local cell may need to be chosen).

The group handover request acknowledgement message transmitted at steps616 and 716 may contain, for example, target local cell radio linkreconfiguration information common to all UEs in the group G2 (such asradio resource configuration, channel configuration, target local cellsystem information (if any), etc.), target local cell mobility controlinformation common to all UEs in the group G2 (such as carrierfrequency, local cell ID, tracking area code, target security algorithm(if any), etc.) and UE specific information relating to the target localcell (such as a new RNTI (if any) for each UE, dedicated RACH preamble(if necessary) for each UE, etc.). Furthermore, in some cases the targetlocal cell VC2 may only be able to accept a subset of the group G2 whichis to be handed over. In such a case, the target local cell may include,in the group handover request acknowledgement message, for example,information recommending particular UEs to be accepted or may indicate alimitation of the number of UEs and (and corresponding resources) whichcan be expected.

The handover command transmitted from the source local cell VC1 to thegroup G2 at steps 618 and 720 contains relevant information from thatincluded in the group handover request acknowledgement message. Ingeneral, the group handover command may be sent by a combination ofgroup specific and UE specific signalling. In particular, theinformation in the group handover command common to all UEs in the groupG2 may be transmitted to all UEs in the group G2 using a first handoverinformation signal (the first handover information being transmitted asa groupcast message or groupcast signalling, for example). The firsthandover information signal includes the target local cell radio linkreconfiguration information (such as radio resource configuration,channel configuration, target local cell system information (if any),etc.), and target local cell mobility control information (such ascarrier frequency, local cell ID, tracking area code, target securityalgorithm (if any), etc.). The first handover information signal may betransmitted as a groupcast message using a specific group-RNTI allocatedto the group G2, for example. Furthermore, if necessary. UE specificinformation (such as a new RNTI (if any) for each UE, dedicated RACHpreamble for each UE (if necessary), etc.) will be sent to eachrespective UE in the group individually using a second handoverinformation signal specific to each UE (this may be implemented usingRRC signalling, for example). Such specific UE information may be usedto implement UE differentiation according to, for example, the datatraffic and QoS requirements for each UE.

As previously mentioned, in order to provide improved efficiency innetwork resource allocation, once the group G2 has been handed over tothe target local cell VC2, the source local cell VC1 may ask itsassociated eNB to re-allocate the resource pool according to its currentdemand (as occurs at steps 626 and 728). The request may contain, forexample, information regarding the UEs still being served by the sourcelocal cell VC1 (in the case of FIGS. 6 and 7, these are the UEsbelonging to group G1) such as the number of such UEs, the resourcesdemands of the group, etc. The re-allocation is then carried out (by theeNB associated with VC1) on the basis of this information.

It will thus be appreciated that in both the case that the handoverdecision is made by the source local cell (as exemplified in FIG. 6) andthe case that the handover decision is made by an eNB (as exemplified inFIG. 7), a significant proportion of the processing for managing grouphandover is offloaded to the local cells of the network. The signallingand processing overhead associated with the conventional networkinfrastructure (in particular, at the eNBs) is thus reduced, leading toimproved handover efficiency.

It will thus be appreciated that, in a first embodiment, the presenttechnique provides a first terminal device (such as UE 114A or 114B) forexchanging signals with a wireless telecommunications network and aplurality of second terminal devices (such as UEs 112A-F). The firstterminal device comprises a transceiver (such as that provided bytransmitter 401 and receiver 402) configured to exchange signals witheach of the plurality of second terminal devices, when the firstterminal device provides a local cell for the plurality of secondterminal devices, and to exchange signals with one or moreinfrastructure equipment (such as eNB 102A and/or 102B) of the wirelesstelecommunications network. The first terminal device also comprises acontroller (such as controller 404) configured to control thetransceiver to receive, from each of the plurality of second terminaldevices served by the first terminal device when providing the localcell, suitability information indicative of the suitability of each ofone or more other terminal devices or infrastructure equipment of thewireless telecommunications network to exchange signals with that secondterminal device to form for that second terminal devices another localcell. The controller is configured to control the transceiver totransmit a handover command to one or more of the plurality of secondterminal devices, the handover command instructing the one or moresecond terminal devices to exchange signals with the wirelesstelecommunications network via an identified more suitable local cell,if one of the one or more other terminal devices or infrastructureequipment of the wireless telecommunications network other than thefirst terminal device is identified as being more suitable for servingthe one or more second terminal devices served by the first terminaldevice. Thus, for example, in the case that the first terminal device isUE 114A, then the other terminal devices or infrastructure equipmentcould include the UE 114B (as another terminal device) and the eNBs 102Aand 102B (as infrastructure equipment). In the case that, say, the UE114B is determined to be a more suitable local cell for one or more ofthe UEs 112A-F (based on the suitability information), then the UE 114Awill transmit a handover command to the one or more of the UEs 112A-Finstructing them to connect to the network via UE 114B instead of via UE114A. UE 114B, in this case, becomes a local cell for these handed overUEs.

A flow chart schematically showing an example process as carried out bythe controller of the first terminal device is shown in FIG. 9A. Theprocess starts at step 900. At step 902, the transceiver is controlledto exchange signals with each of the plurality of second terminaldevices, when the first terminal device provides a local cell for theplurality of second terminal devices, and to exchange signals with oneor more infrastructure equipment of the wireless telecommunicationsnetwork. At step 904, the transceiver is controlled to receive, fromeach of the plurality of second terminal devices served by the firstterminal device when providing the local cell, suitability informationindicative of the suitability of each of one or more other terminaldevices or infrastructure equipment of the wireless telecommunicationsnetwork to exchange signals with that second terminal device to form forthat second terminal devices another local cell. At step 906, it isdetermined whether one of one or more other terminal devices orinfrastructure equipment of the wireless telecommunications networkother than the first terminal device is identified as being moresuitable for serving one or more second terminal devices served by thefirst terminal device. If the determination is positive, then theprocess proceeds to step 908, in which the transceiver is controlled totransmit a handover command to the one or more second terminal devices,the handover command instructing the one or more second terminal devicesto exchange signals with the wireless telecommunications network via theidentified more suitable local cell. The process then ends at step 910.On the other hand, if the determination at step 906 is negative, thenthe process returns to step 902.

In one example, the transceiver of the first terminal device isconfigured to transmit the suitability information to infrastructureequipment of the wireless telecommunications network. The transceiver isalso configured to receive, from the infrastructure equipment,information indicative of the identified more suitable local cell, inthe case that one of the one or more other terminal devices orinfrastructure equipment of the wireless telecommunications networkother than the first terminal device is identified as being moresuitable for serving the one or more second terminal devices served bythe first terminal device. The controller is then configured to controlthe transceiver to transmit the handover command to the one or moresecond terminal devices in response to the transceiver receiving theinformation indicative of the identified more suitable local cell, thehandover command comprising the information indicative of the identifiedmore suitable local cell. Thus, in this case, it is the infrastructureequipment which makes the handover decision, as described with referenceto FIG. 7, for example.

In another example, the controller is configured to determine, on thebasis of the suitability information, whether one of the one or moreother terminal devices or infrastructure equipment of the wirelesstelecommunications network other than the first terminal device is moresuitable for serving the one or more second terminal devices served bythe first terminal device. Thus, in this case, the first terminal deviceitself makes the handover decision, as described with reference to FIG.6, for example.

In one example, the suitability information received from each of theplurality of second terminal devices served by the first terminal devicecomprises an indication of a radio link quality between that secondterminal device and each of the one or more other terminal devices orinfrastructure equipment of the wireless telecommunications network. Foreach second terminal device, one of the other terminal devices orinfrastructure equipment with a higher radio link quality with thatsecond terminal device is biased towards being determined as moresuitable for serving that second terminal device as a local cell thanone of the other terminal devices or infrastructure equipment with alower radio link quality with that second terminal device. In otherwords, the better the radio link quality between a particular one of theother terminal devices or infrastructure equipment and a second terminaldevice, the more likely it is for that particular one of the otherterminal devices or infrastructure equipment to be determined as asuitable local cell for that second terminal device. In one example, theradio link quality between each second terminal device and each of theone or more other terminal devices or infrastructure equipment isdetermined on the basis of an RSRP or RSRQ value as measured andreported by each of the second terminal devices.

In another example, the suitability information received from each ofthe plurality of second terminal devices served by the first terminaldevice comprises an indication of a direction of travel of that secondterminal device relative to at least one of the one or more otherterminal devices or infrastructure equipment of the wirelesstelecommunications network. For each second terminal device, one of theother terminal devices or infrastructure equipment towards which thatsecond terminal device is travelling is biased towards being determinedas more suitable for serving that second terminal device as a local cellthan one of the other terminal devices or infrastructure equipment awayfrom which that second terminal device is travelling. In other words,one of the other terminal devices or infrastructure equipment towardswhich a second terminal device is travelling is more likely to bedetermined as a suitable local cell for that second terminal device thananother one of the other terminal devices or infrastructure equipmentaway from which that second terminal device is travelling.

Furthermore, the suitability information received from each of theplurality of second terminal devices served by the first terminal devicemay comprise an indication of a speed of travel of that second terminaldevice relative to at least one of the one or more other terminaldevices or infrastructure equipment of the wireless telecommunicationsnetwork. For each second terminal device, one of the other terminaldevices or infrastructure equipment towards which that second terminaldevice is travelling with a greater speed is biased towards being (thatis, more likely to be) determined as more suitable for serving thatsecond terminal device as a local cell than one of the other terminaldevices or infrastructure equipment towards which that second terminaldevice is travelling at lower speed. Also, for each second terminaldevice, one of the other terminal devices or infrastructure equipmentaway from which that second terminal device is travelling with a greaterspeed is biased towards being (that is, more likely to be) determined asless suitable for serving that second terminal device as a local cellthan one of the other terminal devices or infrastructure equipment awayfrom which that second terminal device is travelling at lower speed.

It will be appreciated that further variations on this are possible. Forexample, if the speed with which the second terminal device movestowards one of the other terminal devices or infrastructure equipment istoo high, then that terminal device or infrastructure equipment may notbe the most appropriate target network node (since this would result inoverly frequent handover at this network node). There may therefore be,for example, a predetermined maximum speed with which the secondterminal device moves towards one of the other terminal devices orinfrastructure equipment above which that other terminal device orinfrastructure equipment is not determined to be the most appropriatetarget network node.

It is noted that the direction and/or speed of travel of each secondterminal device may be determined using any suitable method (forexample, using changes in GNSS coordinates or monitoring changes in theradio link quality with respect to each of the one or more otherterminal devices or infrastructure equipment of the wirelesstelecommunications network).

In another example, the suitability information received from each ofthe plurality of second terminal devices served by the first terminaldevice comprises a state identifier of that second terminal device, thestate identifier indicating one of a plurality of predetermined possiblestates of that second terminal device. For each second terminal device,one of the other terminal devices or infrastructure equipment with astate identifier matching the state identifier of that second terminaldevice is biased towards being (that is, more likely to be) determinedas a more suitable serving one of the other terminal devices orinfrastructure equipment for that second terminal device than one of theother terminal devices or infrastructure equipment without a stateidentifier matching the state identifier of that second terminal device.For example, a state identifier may indicate one of a plurality ofpredetermined possible geographical locations of each second terminaldevice and each of the one or more other terminal devices orinfrastructure equipment of the wireless telecommunications network. Theplurality of predetermined possible geographical locations may berelatively simple (such as “inside subway station” and “not insidesubway station”, thus allowing second terminal devices to connect via asubway station-specific local cell as they enter the subway station andto connect via a different local cell as the leave the subway station,as previously discussed), or may be more complex.

It is noted that the controller of the first terminal device may use aplurality of different types of suitability information (such as thevarious types discussed above) simultaneously to decide on the mostsuitable local cell for a particular second terminal device. Each typeof suitability information may have equal weightings on the decision or,alternatively, certain types of suitability information may have greaterweightings on the decision than others. For example, the use of a stateidentifier may be given a greater weighting than the other types ofsuitability information (meaning that, for example, a subwaystation-specific local cell will still be determined as the mostsuitable local cell for a particular second terminal device locatedinside the subway station even if the other types of suitabilityinformation indicate that another local cell might be more suitable—suchan arrangement may help data traffic flow, for example).

In the case that one of the one or more other terminal devices orinfrastructure equipment of the wireless telecommunications network isdetermined to be more suitable for serving one or more of the secondterminal devices served by the first terminal device, the transceivermay be configured to transmit, following transmission of the handovercommand to the one or more second terminal devices, a request toinfrastructure equipment of the wireless telecommunications network forcommunication resources used by the first terminal device for exchangingsignals with the handed over one or more second terminal devices to bere-allocated. The transceiver is then also configured to receive, fromthe infrastructure equipment, an acknowledgement message indicating thatthe communication resources used by the first terminal device forexchanging signals with the handed over one or more second terminaldevices have been re-allocated. This is exemplified by steps 610 and 612of FIG. 6, for example.

In a further example of the first embodiment of the present technique,there is provided infrastructure equipment (such as eNB 102A or 102B)for use with a wireless telecommunications network. The infrastructureequipment comprises a transceiver (such as that provided by transmitter406 and receiver 408) configured to receive, from a first terminaldevice (such as UE 114A or 114B) of the wireless telecommunicationsnetwork, the first terminal device being configured to exchange signalswith each of a plurality of second terminal devices (such as UEs 112A-F)of the wireless telecommunications network, when the first terminaldevice provides a local cell for the plurality of second terminaldevices, and to exchange signals with the infrastructure equipment,suitability information indicative of the suitability of one or moreother terminal devices or infrastructure equipment of the wirelesstelecommunications network to exchange signals with each of theplurality of second terminal devices to form for that second terminaldevice another local cell. The infrastructure equipment also comprises acontroller (such as controller 410) configured to determine, on thebasis of the suitability information, whether one of the one or moreother terminal devices or infrastructure equipment of the wirelesstelecommunications network is more suitable for serving one or more ofthe second terminal devices served by the first terminal device. In thecase that one of the one or more other terminal devices orinfrastructure equipment of the wireless telecommunications network isdetermined to be more suitable for serving one or more of the secondterminal devices served by the first terminal device, the controller isconfigured to control the transceiver to transmit information indicativeof the identified one or more other terminal devices or infrastructureequipment to the first terminal device. In this example, theinfrastructure equipment thus makes the handover decision, eNB1 (asshown in FIG. 7) is an example of such infrastructure equipment.

A flow chart schematically showing an example process as carried out bythe controller of the infrastructure equipment is shown in FIG. 9B. Theprocess starts at step 912. At step 914, the transceiver is controlledto receive, from a first terminal device of the wirelesstelecommunications network, the first terminal device being configuredto exchange signals with each of a plurality of second terminal devicesof the wireless telecommunications network, when the first terminaldevice provides a local cell for the plurality of second terminaldevices, and to exchange signals with the infrastructure equipment,suitability information indicative of the suitability of one or moreother terminal devices or infrastructure equipment of the wirelesstelecommunications network to exchange signals with each of theplurality of second terminal devices to form for that second terminaldevice another local cell. At step 916, it is determined, on the basisof the suitability information, whether one of the one or more otherterminal devices or infrastructure equipment of the wirelesstelecommunications network is more suitable for serving one or more ofthe second terminal devices served by the first terminal device. If thedetermination is positive, then the process proceeds to step 916, inwhich the transceiver is controlled to transmit information indicativeof the identified one or more other terminal devices or infrastructureequipment to the first terminal device. The process then ends at step920. On the other hand, if the determination at step 916 is negative,then the process simply ends at step 920 (without implementing step918).

Contention Based Uplink Transmission in Local Cell

As previously mentioned, as well as the need to manage group handoverbetween local cells, there is also a need for a local cell toefficiently use the communication resources made available to it forcommunicating with UEs in the group. At the same time, it is desirableto maintain a low communication latency with respect to the UEs.

One way of achieving this is for the UEs to use contention based (CB)transmission when transmitting signals to the local cell on the PhysicalUplink Shared Channel (PUSCH). CB transmission allows multiple UEs touse the same uplink resources. The assumption is that, most of the time,two UEs will not wish to transmit PUSCH data simultaneously using thosesame resources, and there will therefore be no collision. When there isa collision, however, measures are taken to allow re-transmission of thedata from each UE (using different resources, for example). The resultis that the total number of resources dedicated for use by a particulargroup of UEs (together with any associated signalling) can be reduced.The cost is a small increase in communication latency in the event of acollision (since the data from each UE then needs to be re-transmitted).CB transmission as used for physical uplink shared channel (PUSCH)transmission is discussed in detail in [2], for example.

The characteristics of CB PUSCH as known include:

-   (1) A single set of specific resource blocks (which may be referred    to as a single CB grant) is allocated to UEs for use in CB uplink    transmission. At any one time, a UE that wishes to perform a CB    PUSCH transmission must attempt to use this single CB grant. When    two UEs attempt to perform a CB PUSCH transmission simultaneously    using this single CB grant, there is a collision.-   (2) The CB grant is transmitted by the eNB using the physical    downlink control channel (PDCCH). All the UEs must therefore monitor    the PDCCH for the CB grant. The CB grant may be transmitted either    by dynamic scheduling or semi-persistent scheduling (SPS). If SPS is    used, then the resource pattern of the CB grant is pre-defined with    fixed periodicity and resource block (RB) allocation.-   (3) There is no differentiation between UEs. Each UE has the same    access probability.-   (4) There is no indication on how to harmonize CB PUSCH with    conventional scheduling request (SR) based PUSCH.

As previously mentioned, a local cell is usually triggered in a hot spotarea (that is, an area with high levels of UE data traffic such as asubway station) or in an on-demand manner. CB uplink transmission is asuitable scheme for addressing the low latency requirement of denseareas and/or on-demand traffic. However, due to the characteristics oflocal cells, the use of CB PUSCH needs to be enhanced in the followingways.

-   (1) Collision (as occurs when more than one UE in the group tries to    use the single CB grant) should be reduced as much as possible. Too    much collision reduces the CB based uplink transmission performance.    In general, the use of a CB UL transmission solution reduces the    time spent on scheduling requests and responses. However, too many    collisions will increase the delay (due to the need for UEs to    re-transmit data when there is a collision). Although collisions are    inevitable when using CB transmission, their occurrence should be    reduced as much as possible in order to maintain system performance.    There is therefore a need to reduce the amount of collision for CB    based uplink transmission.-   (2) The signalling from the eNB to the local cell, as well as from    the local cell to each UE, should be minimized. This applies, in    particular, to layer 1 signalling of the CB grant (implemented using    dynamic scheduling or SPS, for example), which consumes    communication resources and also increases power consumption at the    local cell. It is desirable to reduce the power consumption at the    local cell in order to keep it in service for as long as possible.    Hence, there is a need to enhance the signalling relating to the CB    UL transmission in order to reduce communication resource and/or    power consumption.-   (3) The CB uplink transmission from UE to local cell (access link)    and from local cell to eNB (backhaul link) needs more    differentiation. The importance of the backhaul link requires    special dealing of the CB operation.-   (4) The co-existence of CB based and scheduling request (SR) based    uplink transmission should be addressed. The conventional SR based    uplink transmission is necessary according to the current 3GPP    standards, and therefore the harmonization of CB based and SR based    uplink transmission is desirable.

By considering the above, a second embodiment of the present techniqueprovides a CB uplink transmission arrangement for use with a local cell.

With the second embodiment, a semi-static CB grant pool containingmultiple selectable CB resources is allocated for each group of UEs.This CB grant pool is specific for each group and is indicated in thecontrol information from the local cell to the UEs of each group. The CBgrant pool may be valid for a predetermined time period and could bere-configured by layer 1 CB grant signalling (as previously discussed)or layer 3 radio resource control (RRC) signalling, for example.

In one example, for every CB interval, each UE in a group which wishesto perform an uplink (UL) transmission will select one resource from theCB grant pool for the uplink transmission. The local cell will monitorthe pool. If the local cell receives the UL data and successfully decodeit, then an acknowledgement message (ACK) will be sent to the UE. On theother hand, if two UEs select the same resource from the CB grant poolthen a collision occurs. The local cell will not be able to successfullydecode the UL data due to the collision, and will therefore send no ACK.Neither UE will therefore receive an ACK from the local cell, and theUEs will thus contend for resources during the next CB interval in orderto send the UL data. This process is then repeated every CB interval ifconfigured or until all the UL data of UEs is successfully transmitted.

Thus, compared to the known arrangement in which there is a single CBgrant and in which only one UE may use the resources of the single CBgrant at any one time in order to avoid a collision, with the presentembodiment, two UEs may simultaneously select different resources of thesame CB grant pool without causing a collision. The collision rate istherefore reduced whilst still maintaining the advantages (such asreduced resource wastage and reduced SR signalling) associated with CBUL transmission.

It will be appreciated that the size of the pool is a trade off betweenthe collision probability and resource waste. The larger the CB grantpool, the lower the collision probability for a given plurality of UEs,but the larger the potential resource waste. On the other hand, thesmaller the CB grant pool, the higher the collision probability for agiven plurality of UEs, but the smaller the potential resource waste.

It will also be appreciated that, in addition to the UEs connected to aparticular local cell, the local cell itself may be one of a pluralityof UEs and will use CB UL transmission when transmitting data to an eNB.In this case, the local cell may have a higher access probability thanthe other UEs (thus reducing the overall latency associated with UEsconnected to the network via the local cell).

It is noted that the present embodiment also allows for the co-existenceof CB and SR based uplink transmission. In particular, for each UE orlocal cell with CB based UL transmission, the timing relationship of theCB interval with the normal SR based UL scheduling is addressed by thepresent embodiment.

Various features of the present embodiment are described in more detailbelow.

For contention based UL transmission to the local cell, a pre-schedulingCB grant pool will be allocated. This is different from the single CBgrant in conventional CB PUSCH and is also different from, for example,device-to-device (D2D) mode 2 resource allocation. The CB grant pool ofthe present embodiment is signalled by layer 1 signalling in asemi-static manner. The allocation/re-allocation of the pool occurs vialayer 1 signalling which is similar to conventional PDCCH signalling butwhich is only valid for a predetermined period of time. As previouslymentioned, layer 1 signalling may include dynamic scheduling (in whichthe CB grant pool, as defined by its size, location in time andfrequency, may be changed after an interval (that is, in a semi-staticmanner)) or SPS (in which the CB grant pool, together with its pattern(which defines how to use the resources of the radio frame for the CBgrant pool—for example, the periodicity between CB grant pool resourcesof the radio frame) may be changed after an interval (that is, in asemi-static manner)). Layer 3 RRC signalling is another way to configurethe pool allocation/re-allocation. However, the dynamic scheduling ismore suitable for the fast change of CB grant pool configuration that isused with the present embodiment.

To be more specific, after a local cell decides to use CB ULtransmission with a group of UEs connected to it, configurationinformation will be sent from the local cell to each UE (using RRCsignalling, for example) to configure the CB transmission. For example,the configuration information may include parameters such as a groupidentifier (group ID) for allowing each UE in the group to receive thedynamic CB grant pool allocation in the physical layer, CB interval, CBperiodicity, and default release parameters (indicative of, for example,how many blank transmissions are required before the CB grant poolresources are released for other uses). These parameters are groupspecific and may be determined for each group, for example, on the basisof the group characteristics. After transmission of the configurationinformation, physical layer control signalling is sent from the localcell to each UE in the group. The physical layer control signallingcomprises information indicative of the allocated CB grant poolscrambled with the group ID. The information may indicate the grant poolpattern, for example. The pattern could be flexible, continuous (asexemplified in FIG. 8A) or distributed in time and/or frequency (asexemplified in FIG. 8B). By sending a pre-defined pattern as theinformation indicative of the CB grant pool resources (rather thaninformation identifying every CB grant pool resource, for example), theamount of physical layer control signalling is reduced. The CB grantpool configuration may then be changed, for example, in the case thatthere is a new data traffic amount or data traffic type for the UEs inthe group.

An advantage of a distributed CB grant pool (as exemplified in FIG. 8B)is that the resulting distributed CB and SR resources provide greaterflexibility for the local cell to schedule SR UEs on time and frequencyblocks in accordance with, for example, the radio properties of thewireless access interface. It is noted that different types of CB grantpool pattern could be used depending on the desired characteristics ofthe system.

The grouping of each UE may be based on, for example, its locationrelative to other UEs (so that, for example, UEs close to each otherbelong to the same group), the uplink traffic characteristics of each UE(so that, for example, a UE with high levels of uplink traffic isgrouped with other UEs with lower levels of uplink traffic, thusreducing the chance of collision), or according to the buffer statusreported by the UE to the local cell.

It is noted that a similar arrangement to that described above may beimplemented for a local cell when the local cell itself is one of aplurality of UEs which undertake CB based uplink transmission to an eNB.In this case, the CB grant pool will be allocated by the eNB then and asimilar procedure as described above will be applied to each UE(including the local cell).

With the semi-static CB grant pool, for a given group size, thecollision probability will be reduced compared with a single CB grantallocation. Furthermore, the dynamic signalling to address the grantallocation is reduced as well.

In order to reduce the chance of interference between groups (and anyresulting collision), the CB grant pool is different for differentgroups of the same local cell. This alleviates the problem ofinterference for local cells, since local cells generally cover arelatively small area and thus the UE groups themselves are likely to beclose to each other (thus increasing the risk of interference). On theother hand, because the eNB's coverage area is usually larger than thatof a local cell, the multiplexing of the same CB grant pool amonggeographically separated groups of the eNB and/or of different localcells may be possible.

As previously mentioned, the size of the pool allocated to a particularUE group is a trade-off between collision probability and resourcewaste. Too a small pool will lead to a high collision probability thatincreases the latency (due to an increase in the number of ULre-transmissions) whereas too large a pool will lead to resource waste.The pool size depends on the group size as well as the data trafficdemand/activity of the group. Generally, a larger pool will be allocatedto larger group or to a group with a higher data traffic load. A largerpool may be provided by allocating a greater number of resources to thepool. In addition, the periodicity of the pool may be made smaller(resulting in less waiting time for a re-transmission) and/or the CBinterval may be made larger. Furthermore, UEs with larger amounts ofdata to transmit may be reserved with more CB resources following thefirst successful contention (reserving CB grant resources for particularUEs is described in more detail below). The maximum number of groups inone local cell depends on the overall local cell resource size and thesize of each group. In some embodiments, a limit specifying the maximumnumber of groups in one local cell may be implemented.

After the UEs of a particular group are notified of the CB grant pool, aUE of the group that wishes to perform a UL transmission will wait forthe CB interval. For the 1st CB interval that arrives, the UE willrandomly select one CB resource in the pool to transmit the data and thelocal cell will monitor the pool. If the local cell successfully decodesthe data transmitted using the selected resource, then the local cellwill treat the UE as a successful contender and send a positive response(or acknowledgement message) to the UE. Then, according to, for example,a buffer status report (if any) or certain uplink trafficcharacteristics, the local cell may allow the UE to continue to usefurther CB resources in the coming CB intervals. In other words, sincethe local cell knows that the UE has transmitted UL data and maytherefore wish to transmit UL data again, the local cell reservescertain CB resources in the CB grant pool for future use by the UE. Itis only this UE which is allowed to use the reserved CB resources, andthus the UE no longer has to contend with the other UEs in the group forthese CB resources.

The simple way to reserve CB resources in the coming CB intervals is touse the CB resource at the same location in the CB interval as the CBresource originally successfully contended by the UE. Thus, for example,if a CB interval comprises a continuous row of three CB resources, andthe UE successfully contends for the 1^(st) CB resource in the row whenthe 1^(st) CB interval arrives, then the 1^(st) received CB resource ofa predetermined number of future CB interval rows will be reserved foruse by that UE.

Alternatively, CB resources may be reserved via a predetermined hoppingpattern. Thus, for example, if a CB interval again comprises acontinuous row of three CB resources, and the UE successfully contendsfor the 1^(st) CB resource in the row when the 1^(st) CB intervalarrives, then when the 2^(nd) CB interval arrives, the 2^(nd) CBresource in the row may be reserved for the UE, and when the 3^(rd) CBinterval arrives, the 3^(rd) CB resource in the row may be reserved forthe UE. When the 4^(th) CB interval arrives, the 1^(st) received CBsource is again reserved for the UE, and the pattern is repeated.

Once CB resources in future CB intervals have been reserved for aparticular UE of the group, then the local cell will groupcastreservation information to all UEs in the group informing them of the CBresources that have been reserved. The reservation information mayinclude, for example, an identifier of the UE for which the CB resourcesare reserved, a grant reservation period (for example, how many CBintervals the CB resources are reserved for) and information indicativeof the CB resources in each CB interval which are reserved (includingany grant hopping pattern, as appropriate). For the next CB interval(and until after the final CB interval for which the CB resources arereserved has been received), only the UE for which the CB resources havebeen reserved will attempt to transmit UL data using the reservedresources.

In the case that, during the 1^(st) CB interval, two UEs of the grouptry to transmit UL data using the same CB resource, then the local cellwill be unable to decode the data carried by that CB resource. In thiscase, the local cell deduces that there has been a collision on this CBresource and thus sends no response (acknowledgement message). Thecolliding UEs will therefore receive no response—. The colliding UEstherefore determine that there has been a collision and that they willtherefore need to re-transmit their respective UL data. In order for theUL data of each UE to be re-transmitted, each UE must either againcontend for CB resources in a future CB interval, or must transmit an SRand transmit the UL data using conventional scheduled resources. Inparticular, if there is no CB resource available in the next CBinterval, then each UE will decide whether to send an SR and performconventional UL data transmission or wait until a CB resource becomesavailable in the next CB interval. If there is a CB resource availablefor contention, then each UE will decide whether to give up on thecontention and fall back to the conventional SR mode, or to contend theCB resource. The decision could be made according to the number ofavailable CB resources and/or the number of potential competitors, forexample. If a UE decides to again contend for a CB resource, then theywill again follow the procedure detailed above.

If UEs in a group are configured to be allowed to skip the CB resources,then after several consecutive CB intervals without a UL transmissionusing any of the CB resources (or at least using a certain proportion ofthe CB resources), at least a portion of the CB grant pool may bereleased so that the released CB resources may be used for other things(for example, conventional PUSCH resources or CB resources for anothergroup of UEs). If the UEs in a group are not allowed to skip the CBresources, then after several consecutive CB intervals in which paddingmedia access control (MAC) data is received in each of the CB resources(or at least a certain proportion of the CB resources), at least aportion of the CB grant pool may be released. In either case, the numberof CB intervals comprising resources which are skipped or padded withMAC data prior to release of resources from the CB grant pool may beconfigured by the provider of the network, for example.

For the UEs allocated with reserved CB resources, if these UEs do nothave any UL data to transmit, then they may send padding MAC data to thelocal cell using the reserved CB resources. After the local cellreceives such puddings (in one embodiment, for a predetermined number ofconsecutive CB intervals, as configured by the provider of the network,for example), it will groupcast the release of the previously reservedCB resources. In this case, the CB resources still belong to the CBgrant pool. However, all the other UEs in the group may then contend forthe released CB resources in the usual way.

The release of CB resources and reserved CB resources in the waydescribed above leads to a more efficient use of such resources whenthey are no longer being used.

As previously mentioned, a local cell itself may be configured to use aCB grant pool together with other UEs in order to transmit UL data to aneNB. Since the UEs connected to the local cell depend on the local cellfor their connection to the network (the local cell managing controlsignalling of its connected UEs, for example), the local cell may begiven higher priority than the normal UEs when contending for resourcesin the CB grant pool. In particular, local cells who want to contend forthe CB resources of the UL grand pool will have a higher accessprobability than normal UEs (normal UEs being those which do not providea local cell). Furthermore, local cells which successfully contend forCB resources may be allocated more CB resource reservations (forexample, more CB resources in a given CB interval, or reservations whichlast for a larger number of consecutive CB intervals). Also, for localcells which fail to successfully contend a CB resource, the accessprobability for that local cell for the next CB interval may beincreased (for example, doubled). After several times of failure, thelocal cell may send an SR to the eNB so that conventional PUSCHresources may be scheduled for the transmission of the local cell'suplink data.

In some embodiments, there may be a need to distinguish the prioritiesbetween different local cells. For example, a hotspot local cell mayhave a higher priority for obtaining CB resources from the CB grant poolthan a coverage extension local cell, or vice versa. The differentaccess probabilities could be configured for different local cells bythe eNB through RRC signalling, for example. A similar strategy may beapplied for a group of UEs connected to a local cell. That is, one UE inthe group may need to have a higher priority than the other UEs (forexample, a UE belonging to emergency services personnel), and thus theaccess probability for different UEs in the group may be differentiatedso that the higher priority UE has a greater probability of accessing CBresources of the CB grant pool than the other UEs in the group.

There are several ways in which certain UEs may be provided with ahigher access probability with respect to resources of the CB grantpool. In one example, a higher access probability UE (for example, alocal cell amongst normal UEs or a UE belonging to emergency servicespersonnel, as discussed above) may be configured to attempt to transmitUL data using a plurality of resources of the CB grant pool at any onetime whereas the other UEs of the group are configured to attempt totransmit UL data using only a single resource of the CB grant pool atany one time. In another example, each UE may randomly generate a numberfrom 0 to 1 in order to determine whether to contend for a particular CBresource. In an equal access probability case with, for example, fourUEs contending for a particular CB resource, each UE will randomlygenerate a number between 0-1.

If the number generated by a particular UE is less than ¼, then that UEwill attempt a transmission. On the other hand, if there is (say) alocal cell requiring a higher access probability, then if the numbergenerated by the local cell is less than (for example), it will attempta transmission. For each of the three remaining UEs, a transmission willonly be attempted if its respective generated number is less than ⅙.Thus, in general, if n UEs are to have an equal access probability, thenthey will each randomly generate a number between 0 and 1 and willcontend for a particular CB resource when the generated number is lessthan 1/n. On the other hand, when one or more of the n UEs are to have agreater access probability relative to the other UEs, then they willcontend for a particular CB resource when the generated number is lessthan a number greater than 1/n whilst the other UEs will contend for theparticular CB resource when the generated number is less than a numberless than 1/n.

The UEs in each particular group (and who are thus entitled to contendfor resources in a CB grant pool allocated to that group) may also beallocated by dynamic signalling (for example, as part of the dynamicsignalling which allocates the CB grant pool to each UE in the group).

In an embodiment, it is the local cell which decides the ratio betweenSR based and CB based resources. The local cell may decide this ratioaccording to, for example, its data traffic characteristics, QoSrequirements, priorities, link qualities, and so on. Furthermore, in anembodiment, the same UE may be allocated to more than one groupsimultaneously. In this case, the UE would have more than one groupidentifier (that is, one identifier for each respective group to whichit belongs). Such an arrangement is useful, for example, for UEs whichare able to access various services. In this case, a UE may decide tocontend CB resources in different groups so that, for example, resourcesfor transmitting high volume and low latency real time data arecontended for from a group with more CB resources (for example, longerinterval, less periodicity) whilst resources for transmitting normaldata (that is, with less volume and for which higher latency isacceptable) will be contended for from a group with less CB resources.

It will be appreciated that with the present embodiment, the use of theCB grant pool reduces the signalling overhead for each local cell andits associated UEs whilst also reducing the collision rate when comparedto the use of a single CB grant.

It will thus be appreciated that, in a second embodiment, the presenttechnique provides a terminal device (such as one of UEs 112A-F) for usewith a wireless telecommunications network as one of a group of terminaldevices (such as the group of UEs 112A-F). The terminal device comprisesa transceiver (such as that provided by transmitter 401 and receiver402) configured to receive information indicative of a plurality ofcommunication resources, each of the indicated plurality ofcommunication resources being allocated for use by the terminal devicesof the group in transmitting signals to the wireless telecommunicationsnetwork on a contention basis. The plurality of communication resourcesform a CB grant pool. The terminal device also comprises a controller(such as controller 404) configured to control the transceiver totransmit a first signal to the wireless telecommunications network usinga selected one of the allocated communication resources, and todetermine whether the transceiver has received an acknowledgementmessage from the wireless telecommunications network. If it isdetermined that the transceiver has received an acknowledgement message,then the controller determines that the first signal has beensuccessfully received by the wireless telecommunications network. On theother hand, if it is determined that the transceiver has not received anacknowledgement message, then the controller controls the transceiver tore-transmit the first signal to the wireless telecommunications network.The controller is configured in combination with the transceiver toperform a random selection operation by randomly selecting the one ofthe allocated communications resources for transmitting the first signalfrom the plurality of communication resources allocated to the group ofterminal devices.

A flow chart schematically showing an example process as carried out bythe controller of the terminal device is shown in FIG. 10A. The processstarts at step 1000. At step 1002, the transceiver is controlled toreceive information indicative of a plurality of communicationresources, each of the indicated plurality of communication resourcesbeing allocated for use by the terminal devices of the group intransmitting signals to the wireless telecommunications network on acontention basis. At step 1004, the transceiver is then controlled totransmit a first signal to the wireless telecommunications network usinga selected one of the allocated communication resources. At step 1006,it is determined whether the transceiver has received an acknowledgementmessage from the wireless telecommunications network. If thedetermination is positive, then the process moves on to step 1008, inwhich it is determined that the first signal has been successfullyreceived by the wireless telecommunications network. The process thenends at step 1012. On the other hand, if the determination at step 1006is negative, then the process moves on to step 1010, in which thetransceiver is controlled to re-transmit the first signal to thewireless telecommunications network. The process then ends at step 1012.

In one example, the transceiver is configured to receive reservationinformation indicative of one or more of the allocated communicationresources which are reserved for use by another one of the otherterminal devices in the group. The controller is configured to randomlyselect the one of the allocated communication resources from theallocated communication resources which are not reserved for use byanother one of the terminal devices in the group. Furthermore, if it isdetermined that the transceiver has received an acknowledgement message,then the controller is configured to receive updated reservationinformation indicative of one or more of the allocated communicationresources which are reserved for use by the terminal device. Thetransceiver is then controlled to transmit a second signal to thewireless telecommunications network using one of the communicationresources reserved for use by the terminal device.

In one example, the allocated communication resources are periodicallyrepeated in time over one or more consecutive radio frames. This isschematically illustrated in FIGS. 8A and 8B, for example. Furthermore,the one or more of the allocated communication resources reserved foruse by the terminal device are reserved for a predetermined number ofrepeats of the allocated communication resources. The number of repeatsmay be included in the reservation information or, alternatively, knownin advance by the controller, for example. Furthermore, the allocatedcommunication resources may form a portion of a repeating interval ofcommunication resources and may be distributed such that a portion ofthe allocated communication resources are non-consecutive communicationresources in the repeating interval. Such a distributed arrangement isschematically illustrated in FIG. 8B. To be clear, here, the repeatinginterval of communication resources (the length of which is defined bythe “CB periodicity” exemplified in FIG. 8B, not to be confused with the“CB interval” shown in FIG. 8A, which instead defines the length of acontinuous row of allocated resources) comprises both allocated andnon-allocated communication resources. The non-allocated communicationresources are available for use by any UE (using conventionalscheduling, for example), and thus such a distributed arrangement allowsgreater flexibility in the use of the repeating interval ofcommunication resources, as previously explained.

In one example, in the case that no signal has been received via atleast a portion of the allocated communication resources for more than apredetermined number of consecutive repeats of the allocatedcommunication resources, the transceiver is configured to receiveinformation indicating that at least the portion of the allocatedcommunication resources is available for use by other terminal devices.Furthermore, in another example, in the case that no signal has beenreceived via at least a portion of the one or more of the allocatedcommunication resources reserved for use by the terminal device for morethan a predetermined number of consecutive repeats of the allocatedcommunication resources, the transceiver is configured to receiveinformation indicating that at least the portion of the one or morereserved communication resources is available for use by the otherterminal devices of the group in transmitting signals to the wirelesstelecommunications network on a contention basis.

In one example, in order to re-transmit the first signal to the wirelesstelecommunications network, the controller is configured to perform afurther random selection operation to randomly select one of theallocated communication resources and control the transceiver tore-transmit the first signal to the wireless telecommunications networkusing the further selected communication resource. In another example,the first signal may be re-transmitted using conventional scheduledresources.

In a further example of the second embodiment of the present technique,there is provided a terminal device (such as UE 114A or 114B) for usewith a wireless telecommunications network. The terminal devicecomprises a transceiver (such as that provided by transmitter 401 andreceiver 402) configured to transmit information indicative of aplurality of communication resources, each of the indicated plurality ofcommunication resources being allocated for use by each of the terminaldevices in a group of terminal devices (such as the group of terminaldevices 112A-F) in transmitting signals to the wirelesstelecommunications network via the terminal device on a contentionbasis, when the terminal device provides a local cell for the group ofterminal devices. The terminal device comprises a controller configuredto monitor the allocated communication resources for signals received atthe transceiver from the terminal devices of the group, the monitoringcomprising performing an operation (such as decoding) with respect toeach of the allocated communication resources to determine whether asignal has been received by the transceiver via that communicationresource from a single identified one of the terminal devices of thegroup. If it is determined that a signal has been received by thetransceiver via one of the allocated communication resources from asingle identified one of the terminal devices of the group, then thetransceiver is controlled to transmit an acknowledgement message to theidentified terminal device and transmit, to each of the terminal devicesin the group, reservation information indicative of one or more of theallocated communication resources which are reserved for use by theidentified terminal device.

In one example, the allocated communication resources are periodicallyrepeated in time over one or more consecutive radio frames. Again, thisis schematically illustrated in FIGS. 8A and 8B, for example. Eachrepeat of the allocated communication resources is monitored by thecontroller, and the one or more of the allocated communication resourcesreserved for use by the identified terminal device are reserved for apredetermined number of repeats of the allocated communicationresources. Again, the number of repeats may be included in thereservation information or, alternatively, known in advance by thecontroller, for example. The allocated communication resources may forma portion of a repeating interval of communication resources and maydistributed such that a portion of the allocated communication resourcesare non-consecutive communication resources in the repeating interval(as exemplified in FIG. 8B, as previously discussed).

In one example, the controller is configured to monitor the allocatedcommunication resources for signals received from the terminal devicesof the group. The monitoring comprises performing an operation (such asdecoding) with respect to each of the allocated communication resourcesto determine whether a signal has been received by the transceiver viathat communication resource from any of the terminal devices of thegroup. If it is determined that no signal has been received via at leasta portion of the allocated communication resources for more than apredetermined number of consecutive repeats of the allocatedcommunication resources, then the transceiver is controlled to transmitinformation indicating that at least the portion of the allocatedcommunication resources is available for use by other terminal devices.Furthermore, in another example, the controller is configured to monitorthe one or more of the allocated communication resources reserved foruse by the identified terminal device, the monitoring comprisingperforming an operation (such as decoding) with respect to each of theone or more reserved communication resources to determine whether asignal has been received via that communication resource from theidentified terminal device. If it is determined that no signal has beenreceived via at least a portion of the one or more reservedcommunication resources for more than a predetermined number ofconsecutive repeats of the allocated communication resources, then thetransceiver is controlled to transmit information indicating that atleast the portion of the one or more reserved communication resources isavailable for use by the other terminal devices of the group intransmitting signals to the wireless telecommunications network on acontention basis.

A flow chart schematically showing an example process as carried out bythe controller of the terminal device is shown in FIG. 10B. The processstarts at step 1014. At step 1016, the transceiver is controlled totransmit information indicative of a plurality of communicationresources, each of the indicated plurality of communication resourcesbeing allocated for use by each of the terminal devices in a group ofterminal devices in transmitting signals to the wirelesstelecommunications network via the terminal device on a contentionbasis, when the terminal device provides a local cell for the group ofterminal devices. At step 1018, the allocated communication resourcesare monitored for signals received at the transceiver from the terminaldevices of the group, the monitoring comprising performing an operation(such as decoding) with respect to each of the allocated communicationresources to determine whether a signal has been received by thetransceiver via that communication resource from a single identified oneof the terminal devices of the group. At step 1020, it is determinedwhether a signal has been received by the transceiver via one of theallocated communication resources from a single identified one of theterminal devices of the group. If the determination is positive, thenthe transceiver is controlled to transmit an acknowledgement message tothe identified terminal device (step 1022) and transmit, to each of theterminal devices in the group, reservation information indicative of oneor more of the allocated communication resources which are reserved foruse by the identified terminal device (step 1024). The process then endsat step 1026. On the other hand, if the determination at step 1020 isnegative, then the process returns to step 1018.

It will be appreciated that the various processes carried out by thetransceiver and controller of the terminal device (such as UE 114A or114B) which provides a local cell may also be carried out byinfrastructure equipment. In other words, in a further example of thesecond embodiment, there may be provided infrastructure equipment foruse with a wireless telecommunications network, the infrastructureequipment comprising a transceiver (such as that provided by transmitter406 and receiver 408) and a controller (such as controller 410). Thetransceiver is configured to transmit information indicative of aplurality of communication resources, each of the indicated plurality ofcommunication resources being allocated for use by each of the terminaldevices in a group of terminal devices (such as the group of terminaldevices 112A-F) in transmitting signals to the wirelesstelecommunications network via the infrastructure equipment on acontention basis. The controller is configured to monitor the allocatedcommunication resources for signals received at the transceiver from theterminal devices of the group, the monitoring comprising performing anoperation with respect to each of the allocated communication resourcesto determine whether a signal has been received by the transceiver viathat communication resource from a single identified one of the terminaldevices of the group. If it is determined that a signal has beenreceived by the transceiver via one of the allocated communicationresources from a single identified one of the terminal devices of thegroup, then the controller controls the transceiver to transmit anacknowledgement message to the identified terminal device and transmit,to each of the terminal devices in the group, reservation informationindicative of one or more of the allocated communication resources whichare reserved for use by the identified terminal device.

Such infrastructure equipment thus works in exactly the same way as alocal cell terminal device (such as UE 114A or 114B) in terms ofindicating a CB grant pool to a group of terminal devices, monitoringthe resources of the CB grant pool for signals transmitted by one ormore of the group of terminal devices and reserving resources of the CBgrant pool. It will be appreciated that each of the described featuresof the transceiver and controller of a local cell terminal device mayalso be implemented by the transceiver and controller of suchinfrastructure equipment. The CB grant pool of the second embodiment maythus be used with a group of terminal devices no matter whether thoseterminal devices are connected to the network via a local cell or viadirect communication with infrastructure equipment (such as an eNB).

Various features of embodiments of the present technique are defined bythe following numbered clauses:

1. A first terminal device for exchanging signals with a wirelesstelecommunications network and a plurality of second terminal devices,the first terminal device comprising:

-   -   a transceiver configured to exchange signals with each of the        plurality of second terminal devices, when the first terminal        device provides a local cell for providing wireless connectivity        for the plurality of second terminal devices, and to exchange        signals with one or more infrastructure equipment of the        wireless telecommunications network, and    -   a controller configured    -   to control the transceiver to receive, from each of the        plurality of second terminal devices served by the first        terminal device when providing the local cell, suitability        information indicative of the suitability of each of one or more        other terminal devices or infrastructure equipment of the        wireless telecommunications network to exchange signals with        that second terminal device to provide for that second terminal        devices another local cell; and    -   to control the transceiver to transmit a handover command to one        or more of the plurality of second terminal devices, the        handover command instructing the one or more second terminal        devices to exchange signals with the wireless telecommunications        network via an identified more suitable terminal device or        infrastructure equipment for providing a local cell, if one of        the one or more other terminal devices or infrastructure        equipment of the wireless telecommunications network other than        the first terminal device is identified as being more suitable        for serving the one or more second terminal devices served by        the first terminal device.        2. A first terminal device according to clause 1, wherein:    -   the transceiver is configured    -   to transmit the suitability information to infrastructure        equipment of the wireless telecommunications network; and    -   to receive, from the infrastructure equipment, information        indicative of the identified more suitable terminal device or        infrastructure equipment for providing a local cell, in the case        that one of the one or more other terminal devices or        infrastructure equipment of the wireless telecommunications        network other than the first terminal device is identified as        being more suitable for serving the one or more second terminal        devices served by the first terminal device; and    -   the controller is configured to control the transceiver to        transmit the handover command to the one or more second terminal        devices in response to the transceiver receiving the information        indicative of the identified more suitable terminal device or        infrastructure equipment for providing a local cell, the        handover command comprising the information indicative of the        identified more suitable terminal device or infrastructure        equipment for providing a local cell.        3. A first terminal device according to clause 1, wherein the        controller is configured to determine, on the basis of the        suitability information, whether one of the one or more other        terminal devices or infrastructure equipment of the wireless        telecommunications network other than the first terminal device        is more suitable for serving the one or more second terminal        devices served by the first terminal device.        4. A first terminal device according to any preceding clause,        wherein:    -   the suitability information received from each of the plurality        of second terminal devices served by the first terminal device        comprises an indication of a radio link quality between that        second terminal device and each of the one or more other        terminal devices or infrastructure equipment of the wireless        telecommunications network; and    -   for each second terminal device, one of the other terminal        devices or infrastructure equipment with a higher radio link        quality with that second terminal device is biased towards being        determined as more suitable for serving that second terminal        device by providing a a local cell than one of the other        terminal devices or infrastructure equipment with a lower radio        link quality with that second terminal device.        5. A first terminal device according to any preceding clause,        wherein:    -   the suitability information received from each of the plurality        of second terminal devices served by the first terminal device        comprises an indication of a direction of travel of that second        terminal device relative to at least one of the one or more        other terminal devices or infrastructure equipment of the        wireless telecommunications network; and    -   for each second terminal device, one of the other terminal        devices or infrastructure equipment towards which that second        terminal device is travelling is biased towards being determined        as more suitable for serving that second terminal device by        providing a local cell than one of the other terminal devices or        infrastructure equipment away from which that second terminal        device is travelling.        6. A first terminal device according to any preceding clause,        wherein:    -   the suitability information received from each of the plurality        of second terminal devices served by the first terminal device        comprises a state identifier of that second terminal device, the        state identifier indicating one of a plurality of predetermined        possible states of that second terminal device; and    -   for each second terminal device, one of the other terminal        devices or infrastructure equipment with a state identifier        matching the state identifier of that second terminal device is        biased towards being determined as a more suitable serving one        of the other terminal devices or infrastructure equipment for        that second terminal device than one of the other terminal        devices or infrastructure equipment without a state identifier        matching the state identifier of that second terminal device.        7. A first terminal device according to clause 6, wherein the        state identifier indicates one of a plurality of predetermined        possible geographical locations of each of each second terminal        device and each of the one or more other terminal devices or        infrastructure equipment of the wireless telecommunications        network.        8. A first terminal device according to any preceding clause,        wherein, in the case that one of the one or more other terminal        devices or infrastructure equipment of the wireless        telecommunications network is determined to be more suitable for        serving one or more of the second terminal devices served by the        first terminal device,    -   the transceiver is configured:    -   to transmit, following transmission of the handover command to        the one or more second terminal devices, a request to        infrastructure equipment of the wireless telecommunications        network for communication resources used by the first terminal        device for exchanging signals with the handed over one or more        second terminal devices to be re-allocated; and        to receive, from the infrastructure equipment, an        acknowledgement message indicating that the communication        resources used by the first terminal device for exchanging        signals with the handed over one or more second terminal devices        have been re-allocated.        9. A first terminal device according to any preceding clause,        wherein:    -   the handover command transmitted to the one or more of the        plurality of second terminal devices comprises group        information, the group information being common to each of the        one or more second terminal devices, and individual information,        the individual information being specific to each of the one or        more second terminal devices, and    -   the group information is transmitted to each of the one or more        second terminal devices using a first handover information        signal which is transmitted to all of the one or more second        terminal devices, and the individual information is transmitted        to each of the one or more second terminal devices individually        using a second handover information signal specific to each of        the one or more second terminal devices.        10. Infrastructure equipment for use with a wireless        telecommunications network, the infrastructure equipment        comprising:    -   a transceiver configured to receive, from a first terminal        device of the wireless telecommunications network, the first        terminal device being configured to exchange signals with each        of a plurality of second terminal devices of the wireless        telecommunications network, when the first terminal device        provides a local cell for providing wireless connectivity for        the plurality of second terminal devices, and to exchange        signals with the infrastructure equipment, suitability        information indicative of the suitability of one or more other        terminal devices or infrastructure equipment of the wireless        telecommunications network to exchange signals with each of the        plurality of second terminal devices to provide for that second        terminal device another local cell; and    -   a controller configured    -   to determine, on the basis of the suitability information,        whether one of the one or more other terminal devices or        infrastructure equipment of the wireless telecommunications        network is more suitable for serving one or more of the second        terminal devices served by the first terminal device;    -   in the case that one of the one or more other terminal devices        or infrastructure equipment of the wireless telecommunications        network is determined to be more suitable for serving one or        more of the second terminal devices served by the first terminal        device, control the transceiver to transmit information        indicative of the identified one or more other terminal devices        or infrastructure equipment to the first terminal device.        11. Infrastructure equipment according to clause 10, wherein, in        the case that one of the one or more other terminal devices or        infrastructure equipment of the wireless telecommunications        network is determined to be more suitable for serving one or        more of the second terminal devices served by the first terminal        device,    -   the transceiver is configured to receive, from the first        terminal device, following transmission of a handover command        from the first terminal device to the one or more second        terminal devices, the handover command instructing the one or        more second terminal devices to exchange signals with the        wireless telecommunications network via the identified one of        the one or more other terminal devices or infrastructure        equipment, a request for communication resources used by the        first terminal device for exchanging signals with the handed        over one or more second terminal devices to be re-allocated;    -   the controller is configured to, in response to the request,        re-allocate the communication resources used by the first        terminal device for exchanging signals with the handed over one        or more second terminal devices; and    -   the transceiver is configured to transmit, to the first terminal        device, an acknowledgement message indicating that the        communication resources used by the first terminal device for        exchanging signals with the handed over one or more second        terminal devices have been re-allocated.        12. A method of controlling a first terminal device for        exchanging signals with a wireless telecommunications network        and a plurality of second terminal devices, the method        comprising controlling a transceiver of the first terminal        device to    -   exchange signals with each of the plurality of second terminal        devices, when the first terminal device provides a local cell        for providing wireless connectivity for the plurality of second        terminal devices, and to exchange signals with one or more        infrastructure equipment of the wireless telecommunications        network,    -   receive, from each of the plurality of second terminal devices        served by the first terminal device when providing the local        cell, suitability information indicative of the suitability of        each of one or more other terminal devices or infrastructure        equipment of the wireless telecommunications network to exchange        signals with that second terminal device to provide for that        second terminal devices another local cell, and    -   transmit a handover command to one or more of the plurality of        second terminal devices, the handover command instructing the        one or more second terminal devices to exchange signals with the        wireless telecommunications network via an identified more        suitable terminal device or infrastructure equipment for        providing a local cell, if one of the one or more other terminal        devices or infrastructure equipment of the wireless        telecommunications network other than the first terminal device        is identified as being more suitable for serving the one or more        second terminal devices served by the first terminal device.        13. A method of controlling infrastructure equipment for use        with a wireless telecommunications network, the method        comprising:    -   controlling a transceiver of the infrastructure equipment to        receive, from a first terminal device of the wireless        telecommunications network, the first terminal device being        configured to exchange signals with each of a plurality of        second terminal devices of the wireless telecommunications        network, when the first terminal device provides a local cell        for providing wireless connectivity for the plurality of second        terminal devices, and to exchange signals with the        infrastructure equipment, suitability information indicative of        the suitability of one or more other terminal devices or        infrastructure equipment of the wireless telecommunications        network to exchange signals with each of the plurality of second        terminal devices to provide for that second terminal device        another local cell; and    -   determining, on the basis of the suitability information,        whether one of the one or more other terminal devices or        infrastructure equipment of the wireless telecommunications        network is more suitable for serving one or more of the second        terminal devices served by the first terminal device:    -   in the case that one of the one or more other terminal devices        or infrastructure equipment of the wireless telecommunications        network is determined to be more suitable for serving one or        more of the second terminal devices served by the first terminal        device, controlling the transceiver to transmit information        indicative of the identified one or more other terminal devices        or infrastructure equipment to the first terminal device.        14. A wireless telecommunications system comprising a terminal        device according to any one of clauses 1 to 9 and infrastructure        equipment according to clause 10 or 11.        15. A terminal device for use with a wireless telecommunications        network as one of a group of terminal devices, the terminal        device comprising:    -   a transceiver configured to receive information indicative of a        plurality of communication resources, each of the indicated        plurality of communication resources being allocated for use by        the terminal devices of the group in transmitting signals to the        wireless telecommunications network on a contention basis; and    -   a controller configured    -   to control the transceiver to transmit a first signal to the        wireless telecommunications network using a selected one of the        allocated communication resources;    -   to determine whether the transceiver has received an        acknowledgement message from the wireless telecommunications        network;    -   if it is determined that the transceiver has received an        acknowledgement message, determine that the first signal has        been successfully received by the wireless telecommunications        network; and    -   if it is determined that the transceiver has not received an        acknowledgement message, control the transceiver to re-transmit        the first signal to the wireless telecommunications network,    -   wherein the controller is configured in combination with the        transceiver to perform a random selection operation by randomly        selecting the one of the allocated communications resources for        transmitting the first signal from the plurality of        communication resources allocated to the group of terminal        devices.        16. A terminal device according to clause 15, wherein:    -   the transceiver is operable to receive reservation information        indicative of one or more of the allocated communication        resources which are reserved for use by another one of the other        terminal devices in the group;    -   the controller is configured to randomly select the one of the        allocated communication resources from the allocated        communication resources which are not reserved for use by        another one of the terminal devices in the group; and    -   if it is determined that the transceiver has received an        acknowledgement message, then the controller is configured to        receive updated reservation information indicative of one or        more of the allocated communication resources which are reserved        for use by the terminal device, and control the transceiver to        transmit a second signal to the wireless telecommunications        network using one of the communication resources reserved for        use by the terminal device.        17. A terminal device according to clause 16, wherein the        allocated communication resources are periodically repeated in        time over one or more consecutive radio frames, and the one or        more of the allocated communication resources reserved for use        by the terminal device are reserved for a predetermined number        of repeats of the allocated communication resources.        18. A terminal device according to clause 17, wherein the        allocated communication resources form a portion of a repeating        interval of communication resources and are distributed such        that a portion of the allocated communication resources are        non-consecutive communication resources in the repeating        interval.        19. A terminal device according to clause 17 or 18, wherein, in        the case that no signal has been received via at least a portion        of the allocated communication resources for more than a        predetermined number of consecutive repeats of the allocated        communication resources, the transceiver is configured to        receive information indicating that at least the portion of the        allocated communication resources is available for use by other        terminal devices.        20. A terminal device according to any one of clauses 17 to 19,        wherein, in the case that no signal has been received via at        least a portion of the one or more of the allocated        communication resources reserved for use by the terminal device        for more than a predetermined number of consecutive repeats of        the allocated communication resources, the transceiver is        configured to receive information indicating that at least the        portion of the one or more reserved communication resources is        available for use by the other terminal devices of the group in        transmitting signals to the wireless telecommunications network        on a contention basis.        21. A terminal device according to any one of clauses 15 to 20,        wherein, in order to re-transmit the first signal to the        wireless telecommunications network, the controller is        configured to:    -   perform a further random selection operation to randomly select        one of the allocated communication resources; and    -   control the transceiver to re-transmit the first signal to the        wireless telecommunications network using the further selected        communication resource.        22. A terminal device according to any one of clauses 15 to 20,        wherein the controller is configured in combination with the        transceiver to perform the random selection operation in        accordance with an access probability associated with the        terminal device, the access probability of the terminal device        being a probability of the terminal device to attempt to        transmit the first signal using a given one of the allocated        communications resources relative to a probability of each of        the other terminal devices in the group of terminal devices to        attempt to transmit a signal using the given one of the        allocated communications resources.        23. A terminal device according to clause 22, wherein the access        probability of the terminal device is higher relative to the        access probability of each of the other terminal devices in the        group of terminal devices when the terminal device is configured        to provide a local cell in the wireless telecommunications        network.        24. A terminal device according to any one of clauses 15 to 23,        wherein:    -   the transceiver is configured to receive, prior to receiving the        information indicative of the plurality of communication        resources, configuration information comprising a group        identifier (group ID) identifying the group of terminal devices:    -   the received information indicative of the plurality of        communication resources is scrambled using the group ID; and        the controller is configured to descramble the received        information indicative of the plurality of communication        resources using the group ID.        25. A terminal device for use with a wireless telecommunications        network, the terminal device comprising:    -   a transceiver configured to transmit information indicative of a        plurality of communication resources, each of the indicated        plurality of communication resources being allocated for use by        each of the terminal devices in a group of terminal devices in        transmitting signals to the wireless telecommunications network        via the terminal device on a contention basis, when the terminal        device provides a local cell for providing wireless connectivity        for the group of terminal devices; and    -   a controller configured to:    -   monitor the allocated communication resources for signals        received at the transceiver from the terminal devices of the        group, the monitoring comprising performing an operation with        respect to each of the allocated communication resources to        determine whether a signal has been received by the transceiver        via that communication resource from a single identified one of        the terminal devices of the group; and    -   if it is determined that a signal has been received by the        transceiver via one of the allocated communication resources        from a single identified one of the terminal devices of the        group, control the transceiver to transmit an acknowledgement        message to the identified terminal device and transmit, to each        of the terminal devices in the group, reservation information        indicative of one or more of the allocated communication        resources which are reserved for use by the identified terminal        device.        26. A terminal device according to clause 25, wherein the        allocated communication resources are periodically repeated in        time over one or more consecutive radio frames, each repeat of        the allocated communication resources being monitored by the        controller, and the one or more of the allocated communication        resources reserved for use by the identified terminal device are        reserved for a predetermined number of repeats of the allocated        communication resources.        27. A terminal device according to clause 26, wherein the        allocated communication resources form a portion of a repeating        interval of communication resources and are distributed such        that a portion of the allocated communication resources are        non-consecutive communication resources in the repeating        interval.        28. A terminal device according to clause 26 or 27, wherein the        controller is operable to monitor the allocated communication        resources for signals received from the terminal devices of the        group, the monitoring comprising performing an operation with        respect to each of the allocated communication resources to        determine whether a signal has been received by the transceiver        via that communication resource from any of the terminal devices        of the group, and if it is determined that no signal has been        received via at least a portion of the allocated communication        resources for more than a predetermined number of consecutive        repeats of the allocated communication resources, control the        transceiver to transmit information indicating that at least the        portion of the allocated communication resources is available        for use by other terminal devices.        29. A terminal device according to any one of clauses 26 to 28,        wherein the controller is operable to monitor the one or more of        the allocated communication resources reserved for use by the        identified terminal device, the monitoring comprising performing        an operation with respect to each of the one or more reserved        communication resources to determine whether a signal has been        received via that communication resource from the identified        terminal device, and if it is determined that no signal has been        received via at least a portion of the one or more reserved        communication resources for more than a predetermined number of        consecutive repeats of the allocated communication resources,        control the transceiver to transmit information indicating that        at least the portion of the one or more reserved communication        resources is available for use by the other terminal devices of        the group in transmitting signals to the wireless        telecommunications network on a contention basis.        30. A terminal device according to any one of clauses 25 to 29,        wherein:    -   the transceiver is configured to transmit, prior to transmitting        the information indicative of the plurality of communication        resources, configuration information comprising a group        identifier (group ID) identifying the group of terminal devices        to each terminal device in the group of terminal devices; and    -   the controller is configured to scramble the information        indicative of the plurality of communication resources is        scrambled using the group ID prior to transmission of the        information indicative of the plurality of communication        resources.        31. Infrastructure equipment for use with a wireless        telecommunications network, the infrastructure equipment        comprising:    -   a transceiver configured to transmit information indicative of a        plurality of communication resources, each of the indicated        plurality of communication resources being allocated for use by        each of the terminal devices in a group of terminal devices in        transmitting signals to the wireless telecommunications network        via the infrastructure equipment on a contention basis; and    -   a controller configured to:    -   monitor the allocated communication resources for signals        received at the transceiver from the terminal devices of the        group, the monitoring comprising performing an operation with        respect to each of the allocated communication resources to        determine whether a signal has been received by the transceiver        via that communication resource from a single identified one of        the terminal devices of the group; and    -   if it is determined that a signal has been received by the        transceiver via one of the allocated communication resources        from a single identified one of the terminal devices of the        group, control the transceiver to transmit an acknowledgement        message to the identified terminal device and transmit, to each        of the terminal devices in the group, reservation information        indicative of one or more of the allocated communication        resources which are reserved for use by the identified terminal        device.        32. A method of controlling a terminal device for use with a        wireless telecommunications network as one of a group of        terminal devices, the method comprising:    -   controlling a transceiver of the terminal device    -   to receive information indicative of a plurality of        communication resources, each of the indicated plurality of        communication resources being allocated for use by the terminal        devices of the group in transmitting signals to the wireless        telecommunications network on a contention basis; and    -   to transmit a first signal to the wireless telecommunications        network using a selected one of the allocated communication        resources;    -   determining whether the transceiver has received an        acknowledgement message from the wireless telecommunications        network;    -   if it is determined that the transceiver has received an        acknowledgement message, determining that the first signal has        been successfully received by the wireless telecommunications        network; and    -   if it is determined that the transceiver has not received an        acknowledgement message, controlling the transceiver to        re-transmit the first signal to the wireless telecommunications        network,    -   wherein a random selection operation is performed by randomly        selecting the one of the allocated communications resources for        transmitting the first signal from the plurality of        communication resources allocated to the group of terminal        devices.        33. A method of controlling a terminal device for use with a        wireless telecommunications network, the method comprising:    -   controlling a transceiver of the terminal device to transmit        information indicative of a plurality of communication        resources, each of the indicated plurality of communication        resources being allocated for use by each of the terminal        devices in a group of terminal devices in transmitting signals        to the wireless telecommunications network via the terminal        device on a contention basis, when the terminal device provides        a local cell for providing wireless connectivity for the group        of terminal devices;    -   monitoring the allocated communication resources for signals        received at the transceiver from the terminal devices of the        group, the monitoring comprising performing an operation with        respect to each of the allocated communication resources to        determine whether a signal has been received by the transceiver        via that communication resource from a single identified one of        the terminal devices of the group; and    -   if it is determined that a signal has been received by the        transceiver via one of the allocated communication resources        from a single identified one of the terminal devices of the        group, controlling the transceiver to transmit an        acknowledgement message to the identified terminal device and        transmit, to each of the terminal devices in the group,        reservation information indicative of one or more of the        allocated communication resources which are reserved for use by        the identified terminal device.        34. A method of controlling infrastructure equipment for use        with a wireless telecommunications network, the method        comprising:    -   controlling a transceiver of the infrastructure equipment to        transmit information indicative of a plurality of communication        resources, each of the indicated plurality of communication        resources being allocated for use by each of the terminal        devices in a group of terminal devices in transmitting signals        to the wireless telecommunications network via the        infrastructure equipment on a contention basis; and    -   monitoring the allocated communication resources for signals        received at the transceiver of the infrastructure equipment from        the terminal devices of the group, the monitoring comprising        performing an operation with respect to each of the allocated        communication resources to determine whether a signal has been        received by the transceiver via that communication resource from        a single identified one of the terminal devices of the group;        and    -   if it is determined that a signal has been received by the        transceiver of the infrastructure equipment via one of the        allocated communication resources from a single identified one        of the terminal devices of the group, controlling the        transceiver to transmit an acknowledgement message to the        identified terminal device and transmit, to each of the terminal        devices in the group, reservation information indicative of one        or more of the allocated communication resources which are        reserved for use by the identified terminal device.        35. A wireless telecommunications system comprising a terminal        device according to any one of clauses 15 to 24 and one of a        terminal device according to any one of clauses 25 to 30 and        infrastructure equipment according to clause 31.        36. Integrated circuitry for a first terminal device for        exchanging signals with a wireless telecommunications network        and a plurality of second terminal devices, the integrated        circuitry comprising:    -   a transceiver element configured to exchange signals with each        of the plurality of second terminal devices, when the first        terminal device provides a local cell for providing wireless        connectivity for the plurality of second terminal devices, and        to exchange signals with one or more infrastructure equipment of        the wireless telecommunications network, and    -   a controller element configured    -   to control the transceiver element to receive, from each of the        plurality of second terminal devices served by the first        terminal device when providing the local cell, suitability        information indicative of the suitability of each of one or more        other terminal devices or infrastructure equipment of the        wireless telecommunications network to exchange signals with        that second terminal device to provide for that second terminal        devices another local cell; and    -   to control the transceiver element to transmit a handover        command to one or more of the plurality of second terminal        devices, the handover command instructing the one or more second        terminal devices to exchange signals with the wireless        telecommunications network via an identified more suitable        terminal device or infrastructure equipment for providing a        local cell, if one of the one or more other terminal devices or        infrastructure equipment of the wireless telecommunications        network other than the first terminal device is identified as        being more suitable for serving the one or more second terminal        devices served by the first terminal device.        37. Integrated circuitry for infrastructure equipment for use        with a wireless telecommunications network, the integrated        circuitry comprising:    -   a transceiver element configured to receive, from a first        terminal device of the wireless telecommunications network, the        first terminal device being configured to exchange signals with        each of a plurality of second terminal devices of the wireless        telecommunications network, when the first terminal device        provides a local cell for providing wireless connectivity for        the plurality of second terminal devices, and to exchange        signals with the infrastructure equipment, suitability        information indicative of the suitability of one or more other        terminal devices or infrastructure equipment of the wireless        telecommunications network to exchange signals with each of the        plurality of second terminal devices to provide for that second        terminal device another local cell; and    -   a controller element configured    -   to determine, on the basis of the suitability information,        whether one of the one or more other terminal devices or        infrastructure equipment of the wireless telecommunications        network is more suitable for serving one or more of the second        terminal devices served by the first terminal device;    -   in the case that one of the one or more other terminal devices        or infrastructure equipment of the wireless telecommunications        network is determined to be more suitable for serving one or        more of the second terminal devices served by the first terminal        device, control the transceiver element to transmit information        indicative of the identified one or more other terminal devices        or infrastructure equipment to the first terminal device.        38. Integrated circuitry for a terminal device for use with a        wireless telecommunications network as one of a group of        terminal devices, the integrated circuitry comprising:    -   a transceiver element configured to receive information        indicative of a plurality of communication resources, each of        the indicated plurality of communication resources being        allocated for use by the terminal devices of the group in        transmitting signals to the wireless telecommunications network        on a contention basis; and    -   a controller element configured    -   to control the transceiver element to transmit a first signal to        the wireless telecommunications network using a selected one of        the allocated communication resources;    -   to determine whether the transceiver element has received an        acknowledgement message from the wireless telecommunications        network:    -   if it is determined that the transceiver element has received an        acknowledgement message, determine that the first signal has        been successfully received by the wireless telecommunications        network; and    -   if it is determined that the transceiver element has not        received an acknowledgement message, control the transceiver        element to re-transmit the first signal to the wireless        telecommunications network.    -   wherein the controller element is configured in combination with        the transceiver element to perform a random selection operation        by randomly selecting the one of the allocated communications        resources for transmitting the first signal from the plurality        of communication resources allocated to the group of terminal        devices.        39. Integrated circuitry for a terminal device for use with a        wireless telecommunications network, the integrated circuitry        comprising:    -   a transceiver element configured to transmit information        indicative of a plurality of communication resources, each of        the indicated plurality of communication resources being        allocated for use by each of the terminal devices in a group of        terminal devices in transmitting signals to the wireless        telecommunications network via the terminal device on a        contention basis, when the terminal device provides a local cell        for providing wireless connectivity for the group of terminal        devices; and    -   a controller element configured to:    -   monitor the allocated communication resources for signals        received at the transceiver element from the terminal devices of        the group, the monitoring comprising performing an operation        with respect to each of the allocated communication resources to        determine whether a signal has been received by the transceiver        element via that communication resource from a single identified        one of the terminal devices of the group; and    -   if it is determined that a signal has been received by the        transceiver element via one of the allocated communication        resources from a single identified one of the terminal devices        of the group, control the transceiver element to transmit an        acknowledgement message to the identified terminal device and        transmit, to each of the terminal devices in the group,        reservation information indicative of one or more of the        allocated communication resources which are reserved for use by        the identified terminal device.        40. Integrated circuitry for infrastructure equipment for use        with a wireless telecommunications network, the integrated        circuitry comprising:    -   a transceiver element configured to transmit information        indicative of a plurality of communication resources, each of        the indicated plurality of communication resources being        allocated for use by each of the terminal devices in a group of        terminal devices in transmitting signals to the wireless        telecommunications network via the infrastructure equipment on a        contention basis; and    -   a controller element configured to:    -   monitor the allocated communication resources for signals        received at the transceiver element from the terminal devices of        the group, the monitoring comprising performing an operation        with respect to each of the allocated communication resources to        determine whether a signal has been received by the transceiver        element via that communication resource from a single identified        one of the terminal devices of the group; and    -   if it is determined that a signal has been received by the        transceiver element via one of the allocated communication        resources from a single identified one of the terminal devices        of the group, control the transceiver element to transmit an        acknowledgement message to the identified terminal device and        transmit, to each of the terminal devices in the group,        reservation information indicative of one or more of the        allocated communication resources which are reserved for use by        the identified terminal device.

Numerous modifications and variations of the present disclosure arepossible in light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims, the disclosuremay be practiced otherwise than as specifically described herein.

In so far as embodiments of the disclosure have been described as beingimplemented, at least in part, by software-controlled data processingapparatus, it will be appreciated that a non-transitory machine-readablemedium carrying such software, such as an optical disk, a magnetic disk,semiconductor memory or the like, is also considered to represent anembodiment of the present disclosure.

It will be appreciated that the above description for clarity hasdescribed embodiments with reference to different functional units,circuitry and/or processors. However, it will be apparent that anysuitable distribution of functionality between different functionalunits, circuitry and/or processors may be used without detracting fromthe embodiments.

Described embodiments may be implemented in any suitable form includinghardware, software, firmware or any combination of these. Describedembodiments may optionally be implemented at least partly as computersoftware running on one or more data processors and/or digital signalprocessors. The elements and components of any embodiment may bephysically, functionally and logically implemented in any suitable way.Indeed the functionality may be implemented in a single unit, in aplurality of units or as part of other functional units. As such, thedisclosed embodiments may be implemented in a single unit or may bephysically and functionally distributed between different units,circuitry and/or processors.

Although the present disclosure has been described in connection withsome embodiments, it is not intended to be limited to the specific formset forth herein. Additionally, although a feature may appear to bedescribed in connection with particular embodiments, one skilled in theart would recognize that various features of the described embodimentsmay be combined in any manner suitable to implement the technique.

Annex 1:

The simplified structure of the downlink of an LTE wireless accessinterface presented in FIG. 2, also includes an illustration of eachsubframe 201, which comprises a control region 205 for the transmissionof control data, a data region 206 for the transmission of user data,reference signals 207 and synchronisation signals which are interspersedin the control and data regions in accordance with a predeterminedpattern. The control region 204 may contain a number of physicalchannels for the transmission of control data, such as a physicaldownlink control channel (PDCCH), a physical control format indicatorchannel (PCFICH) and a physical HARQ indicator channel (PHICH). The dataregion may contain a number of physical channel for the transmission ofdata, such as a physical downlink shared channel (PDSCH) and a physicalbroadcast channels (PBCH). Although these physical channels provide awide range of functionality to LTE systems, in terms of resourceallocation and the present disclosure PDCCH and PDSCH are most relevant.Further information on the structure and functioning of the physicalchannels of LTE systems can be found in [1].

Resources within the PDSCH may be allocated by an eNodeB to UEs beingserved by the eNodeB. For example, a number of resource blocks of thePDSCH may be allocated to a UE in order that it may receive data that ithas previously requested or data which is being pushed to it by theeNodeB, such as radio resource control (RRC) signalling. In FIG. 2, UE1has been allocated resources 208 of the data region 206, UE2 resources209 and UE resources 210. UEs in a an LTE system may be allocated afraction of the available resources of the PDSCH and therefore UEs arerequired to be informed of the location of their allocated resourceswithin the PDCSH so that only relevant data within the PDSCH is detectedand estimated. In order to inform the UEs of the location of theirallocated communications resources, resource control informationspecifying downlink resource allocations is conveyed across the PDCCH ina form termed downlink control information (DCI), where resourceallocations for a PDSCH are communicated in a preceding PDCCH instancein the same subframe. During a resource allocation procedure, UEs thusmonitor the PDCCH for DCI addressed to them and once such a DCI isdetected, receive the DCI and detect and estimate the data from therelevant part of the PDSCH.

Each uplink subframe may include a plurality of different channels, forexample a physical uplink shared channel (PUSCH) 305, a physical uplinkcontrol channel (PUCCH) 306, and a physical random access channel(PRACH). The physical Uplink Control Channel (PUCCH) may carry controlinformation such as ACK/NACK to the eNodeB for downlink transmissions,scheduling request indicators (SRI) for UEs wishing to be scheduleduplink resources, and feedback of downlink channel state information(CSI) for example. The PUSCH may carry UE uplink data or some uplinkcontrol data. Resources of the PUSCH are granted via PDCCH, such a grantbeing typically triggered by communicating to the network the amount ofdata ready to be transmitted in a buffer at the UE. The PRACH may bescheduled in any of the resources of an uplink frame in accordance witha one of a plurality of PRACH patterns that may be signalled to UE indownlink signalling such as system information blocks. As well asphysical uplink channels, uplink subframes may also include referencesignals. For example, demodulation reference signals (DMRS) 307 andsounding reference signals (SRS) 308 may be present in an uplinksubframe where the DMRS occupy the fourth symbol of a slot in whichPUSCH is transmitted and are used for decoding of PUCCH and PUSCH data,and where SRS are used for uplink channel estimation at the eNodeB.Further information on the structure and functioning of the physicalchannels of LTE systems can be found in [1].

In an analogous manner to the resources of the PDSCH, resources of thePUSCH are required to be scheduled or granted by the serving eNodeB andthus if data is to be transmitted by a UE, resources of the PUSCH arerequired to be granted to the UE by the eNB. At a UE, PUSCH resourceallocation is achieved by the transmission of a scheduling request or abuffer status report to its serving eNodeB. The scheduling request maybe made, when there is insufficient uplink resource for the UE to send abuffer status report, via the transmission of Uplink Control Information(UCI) on the PUCCH when there is no existing PUSCH allocation for theUE, or by transmission directly on the PUSCH when there is an existingPUSCH allocation for the UE. In response to a scheduling request, theeNodeB is configured to allocate a portion of the PUSCH resource to therequesting UE sufficient for transferring a buffer status report andthen inform the UE of the buffer status report resource allocation via aDCI in the PDCCH. Once or if the UE has PUSCH resource adequate to senda buffer status report, the buffer status report is sent to the eNodeBand gives the eNodeB information regarding the amount of data in anuplink buffer or buffers at the UE. After receiving the buffer statusreport, the eNodeB can allocate a portion of the PUSCH resources to thesending UE in order to transmit some of its buffered uplink data andthen inform the UE of the resource allocation via a DCI in the PDCCH.For example, presuming a UE has a connection with the eNodeB, the UEwill first transmit a PUSCH resource request in the PUCCH in the form ofa UCI. The UE will then monitor the PDCCH for an appropriate DCI,extract the details of the PUSCH resource allocation, and transmituplink data, at first comprising a buffer status report, and/or latercomprising a portion of the buffered data, in the allocated resources.

Although similar in structure to downlink subframes, uplink subframeshave a different control structure to downlink subframes, in particularthe upper 309 and lower 310 subcarriers/frequencies/resource blocks ofan uplink subframe are reserved for control signalling rather than theinitial symbols of a downlink subframe. Furthermore, although theresource allocation procedure for the downlink and uplink are relativelysimilar, the actual structure of the resources that may be allocated mayvary due to the different characteristics of the OFDM and SC-FDMinterfaces that are used in the downlink and uplink respectively. InOFDM each subcarrier is individually modulated and therefore it is notnecessary that frequency/subcarrier allocation are contiguous however,in SC-FDM subcarriers are modulation in combination and therefore ifefficient use of the available resources are to be made contiguousfrequency allocations for each UE are preferable.

As a result of the above described wireless interface structure andoperation, one or more UEs may communicate data to one another via acoordinating eNodeB, thus forming a conventional cellulartelecommunications system. Although cellular communications system suchas those based on the previously released LTE standards have beencommercially successful, a number of disadvantages are associated withsuch centralised systems. For example, if two UEs which are in closeproximity wish to communicate with each other, uplink and downlinkresources sufficient to convey the data are required.

Consequently, two portions of the system's resources are being used toconvey a single portion of data. A second disadvantage is that an eNodeBis required if UEs, even when in close proximity, wish to communicatewith one another. These limitations may be problematic when the systemis experiencing high load or eNodeB coverage is not available, forinstance in remote areas or when eNodeBs are not functioning correctly.Overcoming these limitations may increase both the capacity andefficiency of LTE networks but also lead to the creations of new revenuepossibilities for LTE network operators.

REFERENCES

-   [1] LTE for UMTS: OFDMA and SC-FDMA Based Radio Access, Harris Holma    and Antti Toskala, Wiley 2009, ISBN 978-0-470-99401-6.-   [2] R2-156300. Text Proposal capturing outcome of email discussion:    [91bis#34][LTE/LATRED] CB-PUSCH. Anaheim, USA, 16-20 Nov. 2015

1. A first terminal device for exchanging signals with a wirelesstelecommunications network and a plurality of second terminal devices,the first terminal device comprising: a transceiver configured toexchange signals with each of the plurality of second terminal devices,when the first terminal device provides a local cell for providingwireless connectivity for the plurality of second terminal devices, andto exchange signals with one or more infrastructure equipment of thewireless telecommunications network, and a controller configured tocontrol the transceiver to receive, from each of the plurality of secondterminal devices served by the first terminal device when providing thelocal cell, suitability information indicative of the suitability ofeach of one or more other terminal devices or infrastructure equipmentof the wireless telecommunications network to exchange signals with thatsecond terminal device to provide for that second terminal devicesanother local cell; and to control the transceiver to transmit ahandover command to one or more of the plurality of second terminaldevices, the handover command instructing the one or more secondterminal devices to exchange signals with the wirelesstelecommunications network via an identified more suitable terminaldevice or infrastructure equipment for providing a local cell, if one ofthe one or more other terminal devices or infrastructure equipment ofthe wireless telecommunications network other than the first terminaldevice is identified as being more suitable for serving the one or moresecond terminal devices served by the first terminal device.
 2. A firstterminal device according to claim 1, wherein: the transceiver isconfigured to transmit the suitability information to infrastructureequipment of the wireless telecommunications network; and to receive,from the infrastructure equipment, information indicative of theidentified more suitable terminal device or infrastructure equipment forproviding a local cell, in the case that one of the one or more otherterminal devices or infrastructure equipment of the wirelesstelecommunications network other than the first terminal device isidentified as being more suitable for serving the one or more secondterminal devices served by the first terminal device; and the controlleris configured to control the transceiver to transmit the handovercommand to the one or more second terminal devices in response to thetransceiver receiving the information indicative of the identified moresuitable terminal device or infrastructure equipment for providing alocal cell, the handover command comprising the information indicativeof the identified more suitable terminal device or infrastructureequipment for providing a local cell
 3. A first terminal deviceaccording to claim 1, wherein the controller is configured to determine,on the basis of the suitability information, whether one of the one ormore other terminal devices or infrastructure equipment of the wirelesstelecommunications network other than the first terminal device is moresuitable for serving the one or more second terminal devices served bythe first terminal device.
 4. A first terminal device according to claim1, wherein: the suitability information received from each of theplurality of second terminal devices served by the first terminal devicecomprises an indication of a radio link quality between that secondterminal device and each of the one or more other terminal devices orinfrastructure equipment of the wireless telecommunications network; andfor each second terminal device, one of the other terminal devices orinfrastructure equipment with a higher radio link quality with thatsecond terminal device is biased towards being determined as moresuitable for serving that second terminal device by providing a localcell than one of the other terminal devices or infrastructure equipmentwith a lower radio link quality with that second terminal device.
 5. Afirst terminal device according to claim 1, wherein: the suitabilityinformation received from each of the plurality of second terminaldevices served by the first terminal device comprises an indication of adirection of travel of that second terminal device relative to at leastone of the one or more other terminal devices or infrastructureequipment of the wireless telecommunications network, and for eachsecond terminal device, one of the other terminal devices orinfrastructure equipment towards which that second terminal device istravelling is biased towards being determined as more suitable forserving that second terminal device by providing a local cell than oneof the other terminal devices or infrastructure equipment away fromwhich that second terminal device is travelling.
 6. A first terminaldevice according to claim 1, wherein: the suitability informationreceived from each of the plurality of second terminal devices served bythe first terminal device comprises a state identifier of that secondterminal device, the state identifier indicating one of a plurality ofpredetermined possible states of that second terminal device; and foreach second terminal device, one of the other terminal devices orinfrastructure equipment with a state identifier matching the stateidentifier of that second terminal device is biased towards beingdetermined as a more suitable serving one of the other terminal devicesor infrastructure equipment for that second terminal device than one ofthe other terminal devices or infrastructure equipment without a stateidentifier matching the state identifier of that second terminal device.7. A first terminal device according to claim 6, wherein the stateidentifier indicates one of a plurality of predetermined possiblegeographical locations of each of each second terminal device and eachof the one or more other terminal devices or infrastructure equipment ofthe wireless telecommunications network.
 8. A first terminal deviceaccording to claim 1, wherein, in the case that one of the one or moreother terminal devices or infrastructure equipment of the wirelesstelecommunications network is determined to be more suitable for servingone or more of the second terminal devices served by the first terminaldevice, the transceiver is configured: to transmit, followingtransmission of the handover command to the one or more second terminaldevices, a request to infrastructure equipment of the wirelesstelecommunications network for communication resources used by the firstterminal device for exchanging signals with the handed over one or moresecond terminal devices to be re-allocated; and to receive, from theinfrastructure equipment, an acknowledgement message indicating that thecommunication resources used by the first terminal device for exchangingsignals with the handed over one or more second terminal devices havebeen re-allocated.
 9. A first terminal device according to claim 1,wherein: the handover command transmitted to the one or more of theplurality of second terminal devices comprises group information, thegroup information being common to each of the one or more secondterminal devices, and individual information, the individual informationbeing specific to each of the one or more second terminal devices, andthe group information is transmitted to each of the one or more secondterminal devices using a first handover information signal which istransmitted to all of the one or more second terminal devices, and theindividual information is transmitted to each of the one or more secondterminal devices individually using a second handover information signalspecific to each of the one or more second terminal devices. 10-14.(canceled)
 15. A terminal device for use with a wirelesstelecommunications network as one of a group of terminal devices, theterminal device comprising: a transceiver configured to receiveinformation indicative of a plurality of communication resources, eachof the indicated plurality of communication resources being allocatedfor use by the terminal devices of the group in transmitting signals tothe wireless telecommunications network on a contention basis; and acontroller configured to control the transceiver to transmit a firstsignal to the wireless telecommunications network using a selected oneof the allocated communication resources: to determine whether thetransceiver has received an acknowledgement message from the wirelesstelecommunications network: if it is determined that the transceiver hasreceived an acknowledgement message, determine that the first signal hasbeen successfully received by the wireless telecommunications network;and if it is determined that the transceiver has not received anacknowledgement message, control the transceiver to re-transmit thefirst signal to the wireless telecommunications network, wherein thecontroller is configured in combination with the transceiver to performa random selection operation by randomly selecting the one of theallocated communications resources for transmitting the first signalfrom the plurality of communication resources allocated to the group ofterminal devices.
 16. A terminal device according to claim 15, wherein:the transceiver is operable to receive reservation informationindicative of one or more of the allocated communication resources whichare reserved for use by another one of the other terminal devices in thegroup; the controller is configured to randomly select the one of theallocated communication resources from the allocated communicationresources which are not reserved for use by another one of the terminaldevices in the group; and if it is determined that the transceiver hasreceived an acknowledgement message, then the controller is configuredto receive updated reservation information indicative of one or more ofthe allocated communication resources which are reserved for use by theterminal device, and control the transceiver to transmit a second signalto the wireless telecommunications network using one of thecommunication resources reserved for use by the terminal device.
 17. Aterminal device according to claim 16, wherein the allocatedcommunication resources are periodically repeated in time over one ormore consecutive radio frames, and the one or more of the allocatedcommunication resources reserved for use by the terminal device arereserved for a predetermined number of repeats of the allocatedcommunication resources.
 18. A terminal device according to claim 17,wherein the allocated communication resources form a portion of arepeating interval of communication resources and are distributed suchthat a portion of the allocated communication resources arenon-consecutive communication resources in the repeating interval.
 19. Aterminal device according to claim 17, wherein, in the case that nosignal has been received via at least a portion of the allocatedcommunication resources for more than a predetermined number ofconsecutive repeats of the allocated communication resources, thetransceiver is configured to receive information indicating that atleast the portion of the allocated communication resources is availablefor use by other terminal devices.
 20. A terminal device according toclaim 17, wherein, in the case that no signal has been received via atleast a portion of the one or more of the allocated communicationresources reserved for use by the terminal device for more than apredetermined number of consecutive repeats of the allocatedcommunication resources, the transceiver is configured to receiveinformation indicating that at least the portion of the one or morereserved communication resources is available for use by the otherterminal devices of the group in transmitting signals to the wirelesstelecommunications network on a contention basis.
 21. A terminal deviceaccording to claim 15, wherein, in order to re-transmit the first signalto the wireless telecommunications network, the controller is configuredto: perform a further random selection operation to randomly select oneof the allocated communication resources; and control the transceiver tore-transmit the first signal to the wireless telecommunications networkusing the further selected communication resource. 22-23. (canceled) 24.A terminal device according to claim 15, wherein: the transceiver isconfigured to receive, prior to receiving the information indicative ofthe plurality of communication resources, configuration informationcomprising a group identifier (group ID) identifying the group ofterminal devices; the received information indicative of the pluralityof communication resources is scrambled using the group ID; and thecontroller is configured to descramble the received informationindicative of the plurality of communication resources using the groupID.
 25. A terminal device for use with a wireless telecommunicationsnetwork, the terminal device comprising: a transceiver configured totransmit information indicative of a plurality of communicationresources, each of the indicated plurality of communication resourcesbeing allocated for use by each of the terminal devices in a group ofterminal devices in transmitting signals to the wirelesstelecommunications network via the terminal device on a contentionbasis, when the terminal device provides a local cell for providingwireless connectivity for the group of terminal devices; and acontroller configured to: monitor the allocated communication resourcesfor signals received at the transceiver from the terminal devices of thegroup, the monitoring comprising performing an operation with respect toeach of the allocated communication resources to determine whether asignal has been received by the transceiver via that communicationresource from a single identified one of the terminal devices of thegroup; and if it is determined that a signal has been received by thetransceiver via one of the allocated communication resources from asingle identified one of the terminal devices of the group, control thetransceiver to transmit an acknowledgement message to the identifiedterminal device and transmit, to each of the terminal devices in thegroup, reservation information indicative of one or more of theallocated communication resources which are reserved for use by theidentified terminal device.
 26. A terminal device according to claim 25,wherein the allocated communication resources are periodically repeatedin time over one or more consecutive radio frames, each repeat of theallocated communication resources being monitored by the controller, andthe one or more of the allocated communication resources reserved foruse by the identified terminal device are reserved for a predeterminednumber of repeats of the allocated communication resources.
 27. Aterminal device according to claim 26, wherein the allocatedcommunication resources form a portion of a repeating interval ofcommunication resources and are distributed such that a portion of theallocated communication resources are non-consecutive communicationresources in the repeating interval. 28-30. (canceled) 31.Infrastructure equipment for use with a wireless telecommunicationsnetwork, the infrastructure equipment comprising: a transceiverconfigured to transmit information indicative of a plurality ofcommunication resources, each of the indicated plurality ofcommunication resources being allocated for use by each of the terminaldevices in a group of terminal devices in transmitting signals to thewireless telecommunications network via the infrastructure equipment ona contention basis; and a controller configured to: monitor theallocated communication resources for signals received at thetransceiver from the terminal devices of the group, the monitoringcomprising performing an operation with respect to each of the allocatedcommunication resources to determine whether a signal has been receivedby the transceiver via that communication resource from a singleidentified one of the terminal devices of the group; and if it isdetermined that a signal has been received by the transceiver via one ofthe allocated communication resources from a single identified one ofthe terminal devices of the group, control the transceiver to transmitan acknowledgement message to the identified terminal device andtransmit, to each of the terminal devices in the group, reservationinformation indicative of one or more of the allocated communicationresources which are reserved for use by the identified terminal device.32-40. (canceled)